Methods and compositions for potentiating the action of opioid analgesics using iboga alkaloids

ABSTRACT

Methods and compositions for potentiating the effect of an opioid analgesic in a patient undergoing or planning to undergo opioid analgesic therapy using a potentiating amount of iboga alkaloid or pharmaceutically acceptable salt and/or solvate thereof that does not prolong the patient&#39;s QT interval by more than about 50 milliseconds.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.17/341,916, filed Jun. 8, 2021, which is a continuation of U.S. patentapplication Ser. No. 16/882,208, filed May 22, 2020 (now U.S. Pat. No.11,197,866), which is a continuation of U.S. patent application Ser. No.15/093,717, filed Apr. 7, 2016 (now U.S. Pat. No. 10,660,900), which isa continuation-in-part of PCT Application No. PCT/US2015/062783, filedNov. 25, 2015, which claims the benefit under 35 U.S.C. 119(e) of U.S.Provisional Application Ser. No. 62/084,979 filed Nov. 26, 2014;62/119,021 filed Feb. 20, 2015; and 61/996,996 filed Apr. 7, 2015, eachof which is hereby incorporated by reference into this application inits entirety.

FIELD OF THE INVENTION

This invention is directed to methods and compositions for potentiatingthe effect of opioids in a patient undergoing or planning to undergoopioid analgesic treatment for pain. In particular the methods andcompositions include treating the patient with an analgesic opioid orderivative thereof in combination with a potentiating amount of an ibogaalkaloid or pharmaceutically acceptable salt or solvate thereof at asafe and effective dosage. In particular the potentiating amount of theiboga alkaloid or pharmaceutically acceptable salt or solvate thereof issuch that the maximum QT interval prolongation experienced by thepatient is less than about 60 ms, less than about 50 ms, preferably lessthan about 30 ms, more preferably less than about 20 ms.

STATE OF THE ART

Addictive opioid analgesic agents including derivatives thereof (e.g.morphine, hydromorphone) are well-known and exceptionally potentanalgesics. Such opioids operate as mu receptor agonists. Uponadministration, opioids initiate a cascade of biological eventsincluding increased serotonin and dopamine expression. As is well known,continued use of many such opioids (especially at high doses) carries asignificant risk of dependency/addiction. Indeed, potential addiction tosuch opioids is a serious issue that limits the therapeutic use ofaddictive opioids as analgesic agents. For example, the use of morphineas an analgesic is common among end stage patients suffering fromserious pain where addiction is no longer a concern.

Drug tolerance to opioid analgesics is common, and may be psychologicaland/or physiological. A patient who has developed tolerance to theopioid analgesic is not necessarily addicted to or misusing theanalgesic. Drug tolerance occurs when the patient's reaction to the drugis reduced, requiring an increase in dose to achieve the same desiredeffect. There are several potential methods for how tolerance develops,including receptor desensitization, receptor phosphorylation, receptorinternalization or down-regulation, and up-regulation of inhibitorypathways.

Drug tolerance requires that the dosage of analgesic be increased inorder to provide sustained analgesic effect. However, high doses ofopioids may lead to serious complications and side effects, includingphysical dependence, addiction, respiratory depression, nausea,sedation, euphoria or dysphoria, decreased gastrointestinal motility,and itching.

Furthermore, opioid use is associated with a number of unpleasant sideeffects. Side effects include sedation, dizziness, nausea, vomiting,constipation, and respiratory depression.

It would be beneficial to provide a method for potentiating the effectof opioid analgesic(s) in a patient taking one or more opioid analgesicsfor the treatment of pain, such that a lower dose of opioid is requiredto treat the pain.

SUMMARY OF THE INVENTION

This invention is directed, in part, to the use of an iboga alkaloid topotentiate the activity of opioid analgesic agents in a patient takingone or more opioid analgesics wherein the iboga alkaloid is dosed in anamount to potentiate the opioid while maintaining an acceptable QTinterval prolongation. Potentiation of the opioid analgesic may becharacterized by a number of parameters, including but not limited to: adecrease in the amount of opioid analgesic required to treat a similarpain level; improved therapeutic effect from a specified dose of opioidanalgesic, a reduced tolerance to the opioid analgesic; reduceddependency on the opioid analgesic; reduced risk of tolerance to theopioid analgesic; or reduced risk of dependency on the opioid analgesic.

The use of morphine in combination with iboga alkaloids has beendisclosed in non-human subjects such that it did not evaluate the QTinterval prolongation, nor were dosing regimens addressed that affectpotentiation while maintaining an acceptable QT prolongation. Thisinvention is based, at least on part, on the surprising discovery thatiboga alkaloids, e.g. noribogaine, can be administered to a patient at adose that potentiates opioid analgesic action while also minimizing therisk of unsafe QT interval prolongation by the iboga alkaloid.

In one embodiment, the patient has developed or is at risk of developinga tolerance for the analgesic. In a preferred embodiment, the patienthas not yet developed a tolerance to the opioid analgesic. In oneembodiment, the iboga alkaloid is administered throughout opioidtreatment. In one embodiment, the iboga alkaloid is administered aftertolerance (or suspected tolerance) to the opioid has occurred. In anespecially preferred embodiment, the patient is naïve to the opioidanalgesic, i.e., the patient has not been administered an opioidanalgesic for a period of time such that any residual opioid in theblood stream is less than an amount to impart an analgesic effect to thepatient. Preferably, the patient has not been administered an opioidanalgesic within two weeks and preferably within four weeks prior toadministration of iboga alkaloid in combination with an opioidanalgesic.

In one embodiment, administration of the iboga alkaloid inhibitstolerance to the opioid analgesic in the opioid-treated patient whereinthe iboga alkaloid is dosed in an amount to potentiate the opioid whilemaintaining an acceptable QT interval prolongation. As used herein, theterm “inhibits tolerance to the opioid analgesic” includes one or moreof the following:

-   -   the administration of the iboga alkaloid reduces tolerance to        the opioid analgesic;    -   the administration of the iboga alkaloid increases the amount of        time for the patient to become tolerant to the opioid analgesic;    -   the administration of the iboga alkaloid increases the dose of        opioid analgesic at which tolerance to the opioid occurs; and/or    -   the administration of the iboga alkaloid resensitizes the        patient to the opioid.

Pain has physical manifestations, but can also include psychological andemotional factors. The methods and compositions described herein arerelated to treatment of physical manifestations of pain.

In one embodiment, the dose of opioid analgesic that is administered tothe patient is reduced relative to the dose prior to iboga alkaloidadministration, wherein the iboga alkaloid is dosed in an amount topotentiate the opioid while maintaining an acceptable QT intervalprolongation. In one embodiment, the dose of opioid analgesic that isadministered to the patient is reduced relative to the dose that wouldhave been administered in the absence of iboga alkaloid administration.

In one embodiment, gradient doses of the iboga alkaloid and opioidanalgesic are administered to the patient. In some embodiments, thedosage of iboga alkaloid is incrementally increased with a concomitantdecrease in the opioid analgesic dosage. Patients undergoing suchgradient dosing procedures may be monitored by a clinician to ensurepotentiation of the opioid while maintaining an acceptable QT intervalprolongation. The clinician may also monitor for unacceptablerespiratory depression. Analysis of a suitable dosage is well within theskill of the art based on the teachings provided herein, taking intoaccount the age, weight and condition of the patient as well as otherwell known factors.

In one embodiment, effective analgesia can be achieved in a patientwhile resensitizing the patient to the addictive opioid analgesic. Theterm “resensitizing the patient” is used herein to refer to reducing,relieving, attenuating, and/or reversing tolerance to the analgesic. Inone embodiment, the resensitized patient obtains therapeutic effect froma lower dose of the opioid analgesic than before resensitization. In oneembodiment, the resensitized patient obtains improved therapeutic effectfrom the same dose of the opioid analgesic compared to beforeresensitization.

In one embodiment, it is contemplated that co-administration of theiboga alkaloid with the opioid prevents, inhibits or attenuatesdependence on and/or addiction to the opioid analgesic, wherein theiboga alkaloid is dosed in an amount to potentiate the opioid whilemaintaining an acceptable QT interval prolongation. In one embodiment,it is contemplated that administration of the iboga alkaloid increasesthe amount of time for the patient to become dependent on and/oraddicted to the opioid analgesic. In one embodiment, it is contemplatedthat administration of the iboga alkaloid increases the dose of opioidanalgesic at which dependence and/or addiction to the opioid occurs. Inone embodiment, it is contemplated that potentiation of the effect ofthe opioid analgesic allows less of the opioid to be administered to thepatient, further reducing the probability of dependence or addiction(e.g., abuse liability) to the opioid analgesic.

It has been discovered that the use of iboga alkaloids, derivatives, orpharmaceutically acceptable salts and/or solvates thereof imparts adose-dependent prolongation of the treated patient's QT interval,rendering higher dosing of such alkaloids (e.g., noribogaine)unacceptable. A prolonged QT interval can lead to Torsades de Pointes, aserious arrhythmia that can result in death. In a preferred embodimentof the methods and compositions of this invention, the amount of ibogaalkaloids required to achieve one or more of the benefits enumeratedabove is limited such that the patient's QT interval is not prolonged orby more than about 60 milliseconds (ms), preferably not by more than 50ms, and most preferably not by more than 30 ms.

The current invention is predicated on the surprising discovery that theuse of an iboga alkaloid or pharmaceutically acceptable salt and/orsolvate thereof at a dosage that is below that considered effective fortreatment of opioid addiction provides a therapeutic potentiation ofopioid analgesics and exhibits a dose-dependent QT intervalprolongation. This low dose of iboga alkaloid imparts minimal QTinterval prolongation while also reducing the risk of tolerance and/oraddiction to opioid analgesics. Preferably, the dose range that providesboth therapeutic results and an acceptable QT interval prolongation ofless than about 60 milliseconds, less than about 50 milliseconds, lessthan about 30 milliseconds, or less than about 20 milliseconds isbetween about 0.05 mg and about 50 mg per day, or any subrange orsubvalue within the range.

In some embodiments, the ratio of opioid analgesic to iboga alkaloid orpharmaceutically acceptable salt and/or solvate thereof administered tothe patient is between 100:1 and 1:100. In one embodiment, the ratio ofopioid analgesic to iboga alkaloid or pharmaceutically acceptable saltand/or solvate thereof is between 100:1 and 1:50. In one embodiment, theratio of opioid analgesic to iboga alkaloid or pharmaceuticallyacceptable salt and/or solvate thereof is between 100:1 and 1:10. In oneembodiment, the ratio of opioid analgesic to iboga alkaloid orpharmaceutically acceptable salt and/or solvate thereof is between 100:1and 1:1.

Without being bound by theory, it is believed that co-administration ofiboga alkaloid with an opioid as described herein will result inpotentiation of the effect of the opioid with fewer negative sideeffects, reduced tolerance to the opioid, and/or a lower rate ofdependence and/or addiction to the opioid compared to opioidadministration without the iboga alkaloid.

In one embodiment, the iboga alkaloid or pharmaceutically acceptablesalt and/or solvate thereof is administered concurrently with the opioidanalgesic, wherein the iboga alkaloid is dosed in an amount effective topotentiate the opioid while maintaining an acceptable QT intervalprolongation. In one embodiment, a composition comprising an ibogaalkaloid or salt and/or solvate thereof and the opioid analgesic isadministered. Such a combination of both the iboga alkaloid and theanalgesic eliminates the possibility that the patient willself-administer one drug but not the other. It is further contemplatedthat such a combination will reduce the abuse potential of the opioidanalgesic.

Alternatively, in another embodiment such as a clinical setting, theiboga alkaloid or pharmaceutically acceptable salt and/or solvatethereof is administered before or after administration of the analgesic,wherein the iboga alkaloid is dosed in an amount effective to potentiatethe opioid while maintaining an acceptable QT interval prolongation. Forexample, either drug can be administered one, two, three, four, eight,ten, twelve, 24 hours or more after administration of the remainingdrug. In one embodiment, one dose of iboga alkaloid is administered. Inone embodiment, two or more doses of iboga alkaloid are administered.

In one embodiment, the amount of iboga alkaloid administered per day isincreased or decreased over time depending upon factors such as theamount of opioid analgesic administered, the weight, age and conditionof the patient, and other factors well within the skill of the attendingclinician, wherein the amount of iboga alkaloid potentiates the opioidwhile maintaining an acceptable QT interval prolongation. In oneembodiment, the duration of iboga alkaloid treatment is less than aboutfour weeks. In one embodiment, the patient ceases iboga alkaloidadministration for a period of time (e.g., between two days and aboutthree weeks) before restarting the iboga alkaloid treatment.

In some embodiments, the therapeutic dose of iboga alkaloid orpharmaceutically acceptable salt and/or solvate thereof administered tothe patient is an amount sufficient to achieve one or more of thebenefits set forth above and preferably results in an average serumconcentration of no more than about 100 ng/mL, wherein the dose of ibogaalkaloid is an amount that potentiates the opioid while maintaining anacceptable QT interval prolongation. In a preferred embodiment, the doseof iboga alkaloid or pharmaceutically acceptable salt and/or solvatethereof administered to the patient provides an average serumconcentration of no more than about 50 ng/mL.

In one embodiment, the dose of iboga alkaloid or pharmaceuticallyacceptable salt and/or solvate thereof administered to the patientprovides a serum concentration of no more than about 10,000 ng*hour/mL(area under the curve for a period of time, AUC/t) over the periodduring which the iboga alkaloid is administered, wherein the dose ofiboga alkaloid is an amount that potentiates the opioid whilemaintaining an acceptable QT interval prolongation. The period oftreatment may be between about one day and about three weeks or longer.In a preferred embodiment, the period of treatment is about two weeks toabout three weeks. In some embodiments, the iboga alkaloid orpharmaceutically acceptable salt and/or solvate thereof is administeredas long as the opioid analgesic is administered.

In one embodiment, a patient undergoing opioid analgesic treatment forpain is administered a gradient dosage of iboga alkaloid orpharmaceutically acceptable salt and/or solvate thereof over a course oftime. In one embodiment, the gradient dose is an increasing dose ofiboga alkaloid. In one embodiment, the gradient dose is a decreasingdose of iboga alkaloid. The patient may be monitored by a skilledclinican to ensure the iboga alkaloid is dosed in an amount topotentiate the opioid while maintaining an acceptable QT intervalprolongation and without a resultant respiratory depression.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 represents mean noribogaine concentration-time profiles inhealthy patients after single oral dosing with 3 mg (•), 10 mg (∘), 30mg (▾) or 60 mg (Δ) doses. Inset: Individual concentration-time profilesfrom 0-12 h after a 10 mg dose.

FIG. 2 represents mean plasma noribogaine glucuronide concentration-timeprofiles in healthy patients after single oral 30 mg (▾) or 60 mg (Δ)doses.

FIG. 3 illustrates the mean noribogaine concentration-time profile inopioid-addicted patients after a single oral 60 mg (♦), 120 mg (▪), or180 mg (▴) dose of noribogaine.

FIG. 4 illustrates hours to resumption of opioid substitution treatment(OST) for each patient given placebo (•), or a single oral dose ofnoribogaine (60 mg, ▪; 120 mg, ▴; 180 mg, ▾). Center horizontal linerepresents mean. Error bars represent standard deviation.

FIG. 5 illustrates results of noribogaine treatment on final COWS scoresbefore resumption of OST. Boxes include values representing 25%-75%quartiles. Diamonds represent the median, crossbars represent mean.Whiskers represent values within one standard deviation ofmid-quartiles. No outliers were present.

FIG. 6A illustrates of the mean change in total COWS scores over thefirst 6 hours following dosing of noribogaine (60 mg, ▪; 120 mg, ▴; 180mg, ♦) or placebo (•). Data is given relative to baseline COWS score.

FIG. 6B illustrates the mean area under the curve (AUC) over the initial6 hour period after administration of noribogaine or placebo, based onthe COWS score data given in FIG. 6A. A negative change in scoreindicates that withdrawal symptoms subsided over the period.

FIG. 7A illustrates of the mean change in total OOWS scores over thefirst 6 hours following dosing of noribogaine (60 mg, ▪; 120 mg, ▴; 180mg, ♦) or placebo (•). Data is given relative to baseline OOWS score.

FIG. 7B illustrates the mean area under the curve (AUC) over the initial6 hour period after administration of noribogaine or placebo, based onthe OOWS score data given in FIG. 7A. A negative change in scoreindicates that withdrawal symptoms subsided over the period.

FIG. 8A illustrates of the mean change in total SOWS scores over thefirst 6 hours following dosing of noribogaine (60 mg, ▪; 120 mg, ▴; 180mg, ♦) or placebo (•). Data is given relative to baseline SOWS score.

FIG. 8B illustrates the mean area under the curve (AUC) over the initial6 hour period after administration of noribogaine or placebo, based onthe SOWS score data given in FIG. 8A. A negative change in scoreindicates that withdrawal symptoms subsided over the period.

FIG. 9A illustrates the average change in QT interval (ΔQTcl) for eachcohort (60 mg, ▪; 120 mg, ♦; 180 mg, ♦; or placebo, •) over the first 24hours post administration.

FIG. 9B illustrates the relationship between noribogaine concentrationsand ΔΔQTcI with 90% CI.

FIG. 9C is a goodness-of-fit plot for observed and predicted relationbetween noribogaine plasma levels.

FIG. 10 illustrates the projected noribogaine serum concentration (♦)and projected QT prolongation (ΔQTcl) (▪) during the course ofnoribogaine treatment as described in Example 4, case 1.

FIG. 11 illustrates the projected noribogaine serum concentration (♦)and projected QT prolongation (ΔQTcl) (▪) during the course ofnoribogaine treatment as described in Example 4, case 2.

FIG. 12A shows the affinity of noribogaine at the mu (OPRM) opioidreceptor based on competitive inhibition by noribogaine and ibogaine of[³H]-DAMGO binding to OPRM. Data used for the non-linear regressionanalysis are shown as the mean±SEM of each representative experiment(s).Mean±SEM of apparent binding affinity K_(i) values of a least 3experiments are shown in Table 7.

FIG. 12B shows the affinity of noribogaine at the kappa (OPRK) opioidreceptor based on competitive inhibition by noribogaine and ibogaine of[³H]-U69,593 binding to OPRK. Data used for the non-linear regressionanalysis are shown as the mean±SEM of each representative experiment(s).Mean±SEM of apparent binding affinity K_(i) values of a least 3experiments are shown in Table 7.

FIG. 13A shows noribogaine-induced stimulation of [³⁵S]GTPγS binding atthe mu (OPRM) opioid receptors. CHO—K1 cells membrane preparationexpressing the OPRM receptors were stimulated by increasingconcentrations of agonists (DAMGO, Morphine: MOR, Nalmefene: NALM) andtest compounds (Noribogaine: NORI, Ibogaine: IBO; 18-MC). Data used forthe non-linear regression analysis are shown as the mean±SEM of eachrepresentative experiment(s). Mean±SEM of EC₅₀ and E_(max) values of 2to 10 experiments are shown in Table 8.

FIG. 13B shows noribogaine-induced stimulation of [³⁵S]GTPγS binding atthe kappa (OPRK) opioid receptors. CHO—K1 cells membrane preparationexpressing the OPRK receptors were stimulated by increasingconcentrations of agonists (DAMGO, Morphine: MOR, Nalmefene: NALM) andtest compounds (Noribogaine: NORI, Ibogaine: IBO; 18-MC). Data used forthe non-linear regression analysis are shown as the mean±SEM of eachrepresentative experiment(s). Mean±SEM of EC₅₀ and E_(max) values of 2to 10 experiments are shown in Table 8.

FIG. 14A shows noribogaine inhibition of agonist-induced [³⁵S]GTPγSbinding at the mu receptor (OPRM). CHO—K1 cells membrane preparationexpressing the OPRM receptors were stimulated by increasingconcentration of agonists DAMGO and Morphine (MOR) in the presence of150 μM Noribogaine. Data used for the non-linear regression analysis areshown as the mean±SEM of each representative experiment(s) performed intriplicate.

FIG. 14B shows noribogaine inhibition of agonist-induced [³⁵S]GTPγSbinding at the mu receptor (OPRM). [³⁵S]GTPγS binding signal from fourconcentrations of DAMGO (3, 30, 90, and 270 nM) was recorded in thepresence of increasing concentrations of noribogaine. Data used for thenon-linear regression analysis are shown as the mean±SEM of eachrepresentative experiment(s) performed in triplicate.

FIG. 15 shows inhibition of noribogaine-induced [³⁵S]GTPγS binding byOPRK antagonists. (Panel A) Noribogaine dose-response curves wereexamined in the presence of increasing concentrations of Nalmefene(NALM). (Panels B-E) The inhibitory effects of antagonists Naloxone(NALO-30 nM), Nalmefene (NALM-3 nM) and NorBNI (5 nM) were testedagainst increasing concentrations of Noribogaine, and control agonistsU69,593, Dynorphin A, Morphine, and Nalmefene-induced signal. Functionalinhibition constant Ke was extracted for each dose response-curve shiftsand Table 9 represents the mean±SEM of 3-7 experiments. Data used forthe analysis are shown as the mean±SEM of representative experiment(s).

FIG. 16A shows that noribogaine partially inhibits of agonist-induced[³⁵S]GTPγS binding at the kappa receptor (OPRK). Experiments tested theeffects of the partial agonist, Nalmefene (NALM), in the presence ofother agonists. CHO—K1 cells membrane preparation expressing the OPRKreceptors were stimulated by increasing concentration of agonistsDynorphin A (left panel—DYNA) or Morphine (right panel —MOR) in thepresence of 3 nM Nalmefene or 150 μM Noribogaine at ˜5× their EC₅₀.Control antagonist NorBNI was added at 5 nM and 100 μM and compared forright-shift of the agonists dose-responses. Data are shown as themean±SEM of representative experiment(s) performed in triplicate.

FIG. 16B shows that noribogaine partially inhibits of agonist-induced[³⁵S]GTPγS binding at the kappa receptor (OPRK). Experiments tested theeffects of the partial agonist, Nalmefene (NALM), in the presence ofother agonists. Membranes were stimulated by increasing concentrationsof Nalmefene in the presence of agonists U69,593 (100 nM), Morphine(MOR-6 and 5 μM), and Noribogaine (NORI-10 and 100 μM). Data are shownas the mean±SEM of representative experiment(s) performed in triplicate.

FIG. 16C shows that noribogaine partially inhibits of agonist-induced[³⁵S]GTPγS binding at the kappa receptor (OPRK). Experiments tested theeffects of the partial agonist, Noribogaine (NORI), in the presence ofother agonists. CHO—K1 cells membrane preparation expressing the OPRKreceptors were stimulated by increasing concentration of agonistsDynorphin A (left panel—DYNA) or Morphine (right panel—MOR) in thepresence of 3 nM Nalmefene or 150 μM Noribogaine at ˜5× their EC₅₀.Control antagonist 18-MC was added at 5 nM and 100 μM in similarconditions and compared for right-shift of the agonists dose-responses.Data are shown as the mean±SEM of representative experiment(s) performedin triplicate.

FIG. 16D shows that noribogaine partially inhibits of agonist-induced[³⁵S]GTPγS binding at the kappa receptor (OPRK). Experiments tested theeffects of the partial agonist, Noribogaine (NORI), in the presence ofother agonists. Membranes were stimulated by increasing concentrationsof Noribogaine in the presence of agonists U69,593 (100 nM), Morphine(MOR-6 and 5 μM), and Nalmefene (NALM-20 nM). Data are shown as themean±SEM of representative experiment(s) performed in triplicate.

FIG. 17A shows that noribogaine inhibits agonist-induced β-arrestinrecruitment at the mu (OPRM) receptor. CHO—K1 cells expressing the OPRMreceptors were stimulated by increasing concentrations of the referenceagonist [Met]-Enkephalin (MET-K) and test compound Noribogaine (NORI).Reference agonists were applied at a concentration of 80% their EC50 inthe presence of increasing concentrations of noribogaine. Data used forthe non-linear regression analysis are shown as the mean±SEM of onestandardized experiment performed in duplicate.

FIG. 17B shows that noribogaine inhibits agonist-induced β-arrestinrecruitment at the kappa (OPRK) receptors. CHO—K1 cells expressing theOPRK receptors were stimulated by increasing concentrations of thereference agonist Dynorphin A (DYNA) and test compound Noribogaine(NORI). Reference agonists were applied at a concentration of 80% theirEC50 in the presence of increasing concentrations of noribogaine. Dataused for the non-linear regression analysis are shown as the mean±SEM ofone standardized experiment performed in duplicate.

FIG. 18 shows ligand-protein binding contacts of Noribogaine with OPMRover a 12 ns molecular dynamics simulation; data shown are the prevalentinteractions that occur more than 30% in the simulation time.

FIG. 19 shows a binding model of Noribogaine in OPMR extracted from amolecular dynamics simulation.

DETAILED DESCRIPTION OF THE INVENTION

It is to be understood that this invention is not limited to particularembodiments described, as such may, of course, vary. It is also to beunderstood that the terminology used herein is for the purpose ofdescribing particular embodiments only, and is not intended to belimiting, since the scope of this invention will be limited only by theappended claims.

The detailed description of the invention is divided into varioussections only for the reader's convenience and disclosure found in anysection may be combined with that in another section. Unless definedotherwise, all technical and scientific terms used herein have the samemeaning as commonly understood by one of ordinary skill in the art towhich this invention belongs.

It must be noted that as used herein and in the appended claims, thesingular forms “a”, “an”, and “the” include plural referents unless thecontext clearly dictates otherwise. Thus, for example, reference to “acompound” includes a plurality of compounds.

I. Definitions

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. As used herein the followingterms have the following meanings.

The term “about” when used before a numerical designation, e.g.,temperature, time, amount, concentration, and such other, including arange, indicates approximations which may vary by (+) or (−) 10%, 5% or1%.

“Administration” refers to introducing an agent into a patient.Typically, an effective amount is administered, which amount can bedetermined by the treating physician or the like. Any route ofadministration, such as oral, topical, subcutaneous, peritoneal,intra-arterial, inhalation, vaginal, rectal, nasal, introduction intothe cerebrospinal fluid, or instillation into body compartments can beused. The agent may be administered by direct blood stream delivery,e.g. sublingual, intranasal, or intrapulmonary administration.

The related terms and phrases “administering” and “administration of”,when used in connection with a compound or pharmaceutical composition(and grammatical equivalents) refer both to direct administration, whichmay be administration to a patient by a medical professional or byself-administration by the patient, and/or to indirect administration,which may be the act of prescribing a drug. For example, a physician whoinstructs a patient to self-administer a drug and/or provides a patientwith a prescription for a drug is administering the drug to the patient.In addition, “concomitant administration” refers to either simultaneousadministration or administration proximate in time whereby both drugsare therapeutically active in the patient.

“Periodic administration” or “periodically administering” refers tomultiple treatments that occur on a daily, weekly, or monthly basis.Periodic administration may also refer to administration of the ibogaalkaloid or salt and/or solvate thereof one, two, three, or more timesper day. Administration may be via transdermal patch, gum, lozenge,sublingual tablet, intranasal, intrapulmonary, oral administration, orother administration.

“Comprising” or “comprises” is intended to mean that the compositionsand methods include the recited elements, but not excluding others.“Consisting essentially of” when used to define compositions andmethods, shall mean excluding other elements of any essentialsignificance to the combination for the stated purpose. Thus, acomposition consisting essentially of the elements as defined hereinwould not exclude other materials or steps that do not materially affectthe basic and novel characteristic(s) of the claimed invention.“Consisting of” shall mean excluding more than trace elements of otheringredients and substantial method steps. Embodiments defined by each ofthese transition terms are within the scope of this invention.

As used herein, the term “alkyl” refers to monovalent saturatedaliphatic hydrocarbyl groups having from 1 to 12 carbon atoms, 1 to 10carbon atoms, preferably 1 to 6 carbon atoms, and more preferably 1 to 3carbon atoms. This term includes, by way of example, linear and branchedhydrocarbyl groups such as methyl (CH₃—), ethyl (CH₃CH₂—), n-propyl(CH₃CH₂CH₂—), isopropyl ((CH₃)₂CH—), n-butyl (CH₃CH₂CH₂CH₂—), isobutyl((CH₃)₂CHCH₂—), sec-butyl ((CH₃)(CH₃CH₂)CH—), t-butyl ((CH₃)₃C—),n-pentyl (CH₃CH₂CH₂CH₂CH₂—), and neopentyl ((CH₃)₃CCH₂—). The term“C_(x) alkyl” refers to an alkyl group having x carbon atoms, wherein xis an integer, for example, C₃ refers to an alkyl group having 3 carbonatoms.

“Alkenyl” refers to straight or branched hydrocarbyl groups having from2 to 6 carbon atoms and preferably 2 to 4 carbon atoms and having atleast 1 and preferably from 1 to 2 sites of vinyl (>C═C<) unsaturation.Such groups are exemplified, for example, by vinyl, allyl, andbut-3-en-1-yl. Included within this term are the cis and trans isomersor mixtures of these isomers.

“Alkynyl” refers to straight or branched monovalent hydrocarbyl groupshaving from 2 to 6 carbon atoms and preferably 2 to 3 carbon atoms andhaving at least 1 and preferably from 1 to 2 sites of acetylenicunsaturation. Examples of such alkynyl groups include acetylenyl (—CCH),and propargyl (—CH₂CCH).

“Substituted alkyl” refers to an alkyl group having from 1 to 5,preferably 1 to 3, or more preferably 1 to 2 substituents selected fromthe group consisting of alkoxy, substituted alkoxy, acyl, acylamino,acyloxy, amino, substituted amino, aminocarbonyl, aminothiocarbonyl,aminocarbonylamino, aminothiocarbonylamino, aminocarbonyloxy,aminosulfonyl, aminosulfonyloxy, aminosulfonylamino, amidino, aryl,substituted aryl, aryloxy, substituted aryloxy, arylthio, substitutedarylthio, carboxyl, carboxyl ester, (carboxyl ester)amino, (carboxylester)oxy, cyano, cycloalkyl, substituted cycloalkyl, cycloalkyloxy,substituted cycloalkyloxy, cycloalkylthio, substituted cycloalkylthio,cycloalkenyl, substituted cycloalkenyl, cycloalkenyloxy, substitutedcycloalkenyloxy, cycloalkenylthio, substituted cycloalkenylthio,guanidino, substituted guanidino, halo, hydroxy, heteroaryl, substitutedheteroaryl, heteroaryloxy, substituted heteroaryloxy, heteroarylthio,substituted heteroarylthio, heterocyclic, substituted heterocyclic,heterocyclyloxy, substituted heterocyclyloxy, heterocyclylthio,substituted heterocyclylthio, nitro, SO₃H, substituted sulfonyl,sulfonyloxy, thioacyl, thiol, alkylthio, and substituted alkylthio,wherein said substituents are defined herein.

“Substituted alkenyl” refers to alkenyl groups having from 1 to 3substituents, and preferably 1 to 2 substituents, selected from thegroup consisting of alkoxy, substituted alkoxy, acyl, acylamino,acyloxy, amino, substituted amino, aminocarbonyl, aminothiocarbonyl,aminocarbonylamino, aminothiocarbonylamino, aminocarbonyloxy,aminosulfonyl, aminosulfonyloxy, aminosulfonylamino, amidino, aryl,substituted aryl, aryloxy, substituted aryloxy, arylthio, substitutedarylthio, carboxyl, carboxyl ester, (carboxyl ester)amino, (carboxylester)oxy, cyano, cycloalkyl, substituted cycloalkyl, cycloalkyloxy,substituted cycloalkyloxy, cycloalkylthio, substituted cycloalkylthio,cycloalkenyl, substituted cycloalkenyl, cycloalkenyloxy, substitutedcycloalkenyloxy, cycloalkenylthio, substituted cycloalkenylthio,guanidino, substituted guanidino, halo, hydroxy, heteroaryl, substitutedheteroaryl, heteroaryloxy, substituted heteroaryloxy, heteroarylthio,substituted heteroarylthio, heterocyclic, substituted heterocyclic,heterocyclyloxy, substituted heterocyclyloxy, heterocyclylthio,substituted heterocyclylthio, nitro, SO₃H, substituted sulfonyl,sulfonyloxy, thioacyl, thiol, alkylthio, and substituted alkylthio,wherein said substituents are defined herein and with the proviso thatany hydroxy or thiol substitution is not attached to a vinyl(unsaturated) carbon atom.

“Substituted alkynyl” refers to alkynyl groups having from 1 to 3substituents, and preferably 1 to 2 substituents, selected from thegroup consisting of alkoxy, substituted alkoxy, acyl, acylamino,acyloxy, amino, substituted amino, aminocarbonyl, aminothiocarbonyl,aminocarbonylamino, aminothiocarbonylamino, aminocarbonyloxy,aminosulfonyl, aminosulfonyloxy, aminosulfonylamino, amidino, aryl,substituted aryl, aryloxy, substituted aryloxy, arylthio, substitutedarylthio, carboxyl, carboxyl ester, (carboxyl ester)amino, (carboxylester)oxy, cyano, cycloalkyl, substituted cycloalkyl, cycloalkyloxy,substituted cycloalkyloxy, cycloalkylthio, substituted cycloalkylthio,cycloalkenyl, substituted cycloalkenyl, cycloalkenyloxy, substitutedcycloalkenyloxy, cycloalkenylthio, substituted cycloalkenylthio,guanidino, substituted guanidino, halo, hydroxy, heteroaryl, substitutedheteroaryl, heteroaryloxy, substituted heteroaryloxy, heteroarylthio,substituted heteroarylthio, heterocyclic, substituted heterocyclic,heterocyclyloxy, substituted heterocyclyloxy, heterocyclylthio,substituted heterocyclylthio, nitro, SO₃H, substituted sulfonyl,sulfonyloxy, thioacyl, thiol, alkylthio, and substituted alkylthio,wherein said substituents are defined herein and with the proviso thatany hydroxy or thiol substitution is not attached to an acetyleniccarbon atom.

“Alkoxy” refers to the group —O-alkyl wherein alkyl is defined herein.Alkoxy includes, by way of example, methoxy, ethoxy, n-propoxy,isopropoxy, n-butoxy, t-butoxy, sec-butoxy, and n-pentoxy.

“Substituted alkoxy” refers to the group —O-(substituted alkyl) whereinsubstituted alkyl is defined herein.

“Acyl” refers to the groups H—C(O)—, alkyl-C(O)—, substitutedalkyl-C(O)—, alkenyl-C(O)—, substituted alkenyl-C(O)—, alkynyl-C(O)—,substituted alkynyl-C(O)—, cycloalkyl-C(O)—, substitutedcycloalkyl-C(O)—, cycloalkenyl-C(O)—, substituted cycloalkenyl-C(O)—,aryl-C(O)—, substituted aryl-C(O)—, heteroaryl-C(O)—, substitutedheteroaryl-C(O)—, heterocyclic-C(O)—, and substitutedheterocyclic-C(O)—, wherein alkyl, substituted alkyl, alkenyl,substituted alkenyl, alkynyl, substituted alkynyl, cycloalkyl,substituted cycloalkyl, cycloalkenyl, substituted cycloalkenyl, aryl,substituted aryl, heteroaryl, substituted heteroaryl, heterocyclic, andsubstituted heterocyclic are as defined herein. Acyl includes the“acetyl” group CH₃C(O)—.

“Acylamino” refers to the groups —NR³⁸C(O)alkyl, —NR³⁸C(O)substitutedalkyl, —NR³⁸C(O)cycloalkyl, —NR³⁸C(O)substituted cycloalkyl,—NR³⁸C(O)cycloalkenyl, —NR³⁸C(O)substituted cycloalkenyl,—NR³⁸C(O)alkenyl, —NR³⁸C(O)substituted alkenyl, —NR³⁸C(O)alkynyl,—NR³⁸C(O)substituted alkynyl, —NR³⁸C(O)aryl, —NR³⁸C(O)substituted aryl,—NR³⁸C(O)heteroaryl, —NR³⁸C(O)substituted heteroaryl,—NR³⁸C(O)heterocyclic, and —NR³⁸C(O)substituted heterocyclic wherein R³⁸is hydrogen or alkyl and wherein alkyl, substituted alkyl, alkenyl,substituted alkenyl, alkynyl, substituted alkynyl, cycloalkyl,substituted cycloalkyl, cycloalkenyl, substituted cycloalkenyl, aryl,substituted aryl, heteroaryl, substituted heteroaryl, heterocyclic, andsubstituted heterocyclic are as defined herein.

“Acyloxy” refers to the groups alkyl-C(O)O—, substituted alkyl-C(O)O—,alkenyl-C(O)O—, substituted alkenyl-C(O)O—, alkynyl-C(O)O—, substitutedalkynyl-C(O)O—, aryl-C(O)O—, substituted aryl-C(O)O—, cycloalkyl-C(O)O—,substituted cycloalkyl-C(O)O—, cycloalkenyl-C(O)O—, substitutedcycloalkenyl-C(O)O—, heteroaryl-C(O)O—, substituted heteroaryl-C(O)O—,heterocyclic-C(O)O—, and substituted heterocyclic-C(O)O— wherein alkyl,substituted alkyl, alkenyl, substituted alkenyl, alkynyl, substitutedalkynyl, cycloalkyl, substituted cycloalkyl, cycloalkenyl, substitutedcycloalkenyl, aryl, substituted aryl, heteroaryl, substitutedheteroaryl, heterocyclic, and substituted heterocyclic are as definedherein.

“Amino” refers to the group —NH₂.

“Substituted amino” refers to the group —NR³⁹R⁴⁰ where R³⁹ and R⁴⁰ areindependently selected from the group consisting of hydrogen, alkyl,substituted alkyl, alkenyl, substituted alkenyl, alkynyl, substitutedalkynyl, aryl, substituted aryl, cycloalkyl, substituted cycloalkyl,cycloalkenyl, substituted cycloalkenyl, heteroaryl, substitutedheteroaryl, heterocyclic, substituted heterocyclic, —SO₂-alkyl,—SO₂-substituted alkyl, —SO₂-alkenyl, —SO₂-substituted alkenyl,—SO₂-cycloalkyl, —SO₂-substituted cycloalkyl, —SO₂-cycloalkenyl,—SO₂-substituted cylcoalkenyl, —SO₂-aryl, —SO₂-substituted aryl,—SO₂-heteroaryl, —SO₂-substituted heteroaryl, —SO₂-heterocyclic, and—SO₂-substituted heterocyclic and wherein R³⁹ and R⁴⁰ are optionallyjoined, together with the nitrogen bound thereto to form a heterocyclicor substituted heterocyclic group, provided that R³⁹ and R⁴⁰ are bothnot hydrogen, and wherein alkyl, substituted alkyl, alkenyl, substitutedalkenyl, alkynyl, substituted alkynyl, cycloalkyl, substitutedcycloalkyl, cycloalkenyl, substituted cycloalkenyl, aryl, substitutedaryl, heteroaryl, substituted heteroaryl, heterocyclic, and substitutedheterocyclic are as defined herein. When R³⁹ is hydrogen and R⁴⁰ isalkyl, the substituted amino group is sometimes referred to herein asalkylamino. When R³⁹ and R⁴⁰ are alkyl, the substituted amino group issometimes referred to herein as dialkylamino. When referring to amonosubstituted amino, it is meant that either R³⁹ or R⁴⁰ is hydrogenbut not both. When referring to a disubstituted amino, it is meant thatneither R³⁹ nor R⁴⁰ are hydrogen.

“Aminocarbonyl” refers to the group —C(O)NR⁴¹R⁴² where R⁴¹ and R⁴² areindependently selected from the group consisting of hydrogen, alkyl,substituted alkyl, alkenyl, substituted alkenyl, alkynyl, substitutedalkynyl, aryl, substituted aryl, cycloalkyl, substituted cycloalkyl,cycloalkenyl, substituted cycloalkenyl, heteroaryl, substitutedheteroaryl, heterocyclic, and substituted heterocyclic and where R⁴¹ andR⁴² are optionally joined together with the nitrogen bound thereto toform a heterocyclic or substituted heterocyclic group, and whereinalkyl, substituted alkyl, alkenyl, substituted alkenyl, alkynyl,substituted alkynyl, cycloalkyl, substituted cycloalkyl, cycloalkenyl,substituted cycloalkenyl, aryl, substituted aryl, heteroaryl,substituted heteroaryl, heterocyclic, and substituted heterocyclic areas defined herein.

“Aminothiocarbonyl” refers to the group —C(S)NR⁴¹R⁴² where R⁴¹ and R⁴²are independently selected from the group consisting of hydrogen, alkyl,substituted alkyl, alkenyl, substituted alkenyl, alkynyl, substitutedalkynyl, aryl, substituted aryl, cycloalkyl, substituted cycloalkyl,cycloalkenyl, substituted cycloalkenyl, heteroaryl, substitutedheteroaryl, heterocyclic, and substituted heterocyclic and where R⁴¹ andR⁴² are optionally joined together with the nitrogen bound thereto toform a heterocyclic or substituted heterocyclic group, and whereinalkyl, substituted alkyl, alkenyl, substituted alkenyl, alkynyl,substituted alkynyl, cycloalkyl, substituted cycloalkyl, cycloalkenyl,substituted cycloalkenyl, aryl, substituted aryl, heteroaryl,substituted heteroaryl, heterocyclic, and substituted heterocyclic areas defined herein.

“Aminocarbonylamino” refers to the group —NR³⁸C(O)NR⁴¹R⁴² where R³⁸ ishydrogen or alkyl and R⁴¹ and R⁴² are independently selected from thegroup consisting of hydrogen, alkyl, substituted alkyl, alkenyl,substituted alkenyl, alkynyl, substituted alkynyl, aryl, substitutedaryl, cycloalkyl, substituted cycloalkyl, cycloalkenyl, substitutedcycloalkenyl, heteroaryl, substituted heteroaryl, heterocyclic, andsubstituted heterocyclic and where R⁴¹ and R⁴² are optionally joinedtogether with the nitrogen bound thereto to form a heterocyclic orsubstituted heterocyclic group, and wherein alkyl, substituted alkyl,alkenyl, substituted alkenyl, alkynyl, substituted alkynyl, cycloalkyl,substituted cycloalkyl, cycloalkenyl, substituted cycloalkenyl, aryl,substituted aryl, heteroaryl, substituted heteroaryl, heterocyclic, andsubstituted heterocyclic are as defined herein.

“Aminothiocarbonylamino” refers to the group —NR³⁸C(S)NR⁴¹R⁴² where R³⁸is hydrogen or alkyl and R⁴¹ and R⁴² are independently selected from thegroup consisting of hydrogen, alkyl, substituted alkyl, alkenyl,substituted alkenyl, alkynyl, substituted alkynyl, aryl, substitutedaryl, cycloalkyl, substituted cycloalkyl, cycloalkenyl, substitutedcycloalkenyl, heteroaryl, substituted heteroaryl, heterocyclic, andsubstituted heterocyclic and where R⁴¹ and R⁴² are optionally joinedtogether with the nitrogen bound thereto to form a heterocyclic orsubstituted heterocyclic group, and wherein alkyl, substituted alkyl,alkenyl, substituted alkenyl, alkynyl, substituted alkynyl, cycloalkyl,substituted cycloalkyl, cycloalkenyl, substituted cycloalkenyl, aryl,substituted aryl, heteroaryl, substituted heteroaryl, heterocyclic, andsubstituted heterocyclic are as defined herein.

“Aminocarbonyloxy” refers to the group —O—C(O)NR⁴¹R⁴² where R⁴¹ and R⁴²are independently selected from the group consisting of hydrogen, alkyl,substituted alkyl, alkenyl, substituted alkenyl, alkynyl, substitutedalkynyl, aryl, substituted aryl, cycloalkyl, substituted cycloalkyl,cycloalkenyl, substituted cycloalkenyl, heteroaryl, substitutedheteroaryl, heterocyclic, and substituted heterocyclic and where R⁴¹ andR⁴² are optionally joined together with the nitrogen bound thereto toform a heterocyclic or substituted heterocyclic group, and whereinalkyl, substituted alkyl, alkenyl, substituted alkenyl, alkynyl,substituted alkynyl, cycloalkyl, substituted cycloalkyl, cycloalkenyl,substituted cycloalkenyl, aryl, substituted aryl, heteroaryl,substituted heteroaryl, heterocyclic, and substituted heterocyclic areas defined herein.

“Aminosulfonyl” refers to the group —SO₂NR⁴¹R⁴² where R⁴¹ and R⁴² areindependently selected from the group consisting of hydrogen, alkyl,substituted alkyl, alkenyl, substituted alkenyl, alkynyl, substitutedalkynyl, aryl, substituted aryl, cycloalkyl, substituted cycloalkyl,cycloalkenyl, substituted cycloalkenyl, heteroaryl, substitutedheteroaryl, heterocyclic, and substituted heterocyclic and where R⁴¹ andR⁴² are optionally joined together with the nitrogen bound thereto toform a heterocyclic or substituted heterocyclic group, and whereinalkyl, substituted alkyl, alkenyl, substituted alkenyl, alkynyl,substituted alkynyl, cycloalkyl, substituted cycloalkyl, cycloalkenyl,substituted cycloalkenyl, aryl, substituted aryl, heteroaryl,substituted heteroaryl, heterocyclic, and substituted heterocyclic areas defined herein.

“Aminosulfonyloxy” refers to the group —O—SO₂NR⁴¹R⁴² where R⁴¹ and R⁴²are independently selected from the group consisting of hydrogen, alkyl,substituted alkyl, alkenyl, substituted alkenyl, alkynyl, substitutedalkynyl, aryl, substituted aryl, cycloalkyl, substituted cycloalkyl,cycloalkenyl, substituted cycloalkenyl, heteroaryl, substitutedheteroaryl, heterocyclic, and substituted heterocyclic and where R⁴¹ andR⁴² are optionally joined together with the nitrogen bound thereto toform a heterocyclic or substituted heterocyclic group, and whereinalkyl, substituted alkyl, alkenyl, substituted alkenyl, alkynyl,substituted alkynyl, cycloalkyl, substituted cycloalkyl, cycloalkenyl,substituted cycloalkenyl, aryl, substituted aryl, heteroaryl,substituted heteroaryl, heterocyclic, and substituted heterocyclic areas defined herein.

“Aminosulfonylamino” refers to the group —NR³⁸—SO₂NR⁴¹R⁴² where R³⁸ ishydrogen or alkyl and R⁴¹ and R⁴² are independently selected from thegroup consisting of hydrogen, alkyl, substituted alkyl, alkenyl,substituted alkenyl, alkynyl, substituted alkynyl, aryl, substitutedaryl, cycloalkyl, substituted cycloalkyl, cycloalkenyl, substitutedcycloalkenyl, heteroaryl, substituted heteroaryl, heterocyclic, andsubstituted heterocyclic and where R⁴¹ and R⁴² are optionally joinedtogether with the nitrogen bound thereto to form a heterocyclic orsubstituted heterocyclic group, and wherein alkyl, substituted alkyl,alkenyl, substituted alkenyl, alkynyl, substituted alkynyl, cycloalkyl,substituted cycloalkyl, cycloalkenyl, substituted cycloalkenyl, aryl,substituted aryl, heteroaryl, substituted heteroaryl, heterocyclic, andsubstituted heterocyclic are as defined herein.

“Amidino” refers to the group —C(═NR⁴³)NR⁴¹R⁴² where R⁴¹, R⁴², and R⁴³are independently selected from the group consisting of hydrogen, alkyl,substituted alkyl, alkenyl, substituted alkenyl, alkynyl, substitutedalkynyl, aryl, substituted aryl, cycloalkyl, substituted cycloalkyl,cycloalkenyl, substituted cycloalkenyl, heteroaryl, substitutedheteroaryl, heterocyclic, and substituted heterocyclic and where R⁴¹ andR⁴² are optionally joined together with the nitrogen bound thereto toform a heterocyclic or substituted heterocyclic group, and whereinalkyl, substituted alkyl, alkenyl, substituted alkenyl, alkynyl,substituted alkynyl, cycloalkyl, substituted cycloalkyl, cycloalkenyl,substituted cycloalkenyl, aryl, substituted aryl, heteroaryl,substituted heteroaryl, heterocyclic, and substituted heterocyclic areas defined herein.

“Aryl” or “Ar” refers to a monovalent aromatic carbocyclic group of from6 to 14 carbon atoms having a single ring (e.g., phenyl) or multiplecondensed rings (e.g., naphthyl or anthryl) which condensed rings may ormay not be aromatic (e.g., 2-benzoxazolinone,2H-1,4-benzoxazin-3(4H)-one-7-yl, and the like) provided that the pointof attachment is at an aromatic carbon atom. Preferred aryl groupsinclude phenyl and naphthyl.

“Substituted aryl” refers to aryl groups which are substituted with 1 to5, preferably 1 to 3, or more preferably 1 to 2 substituents selectedfrom the group consisting of alkyl, substituted alkyl, alkenyl,substituted alkenyl, alkynyl, substituted alkynyl, alkoxy, substitutedalkoxy, acyl, acylamino, acyloxy, amino, substituted amino,aminocarbonyl, aminothiocarbonyl, aminocarbonylamino,aminothiocarbonylamino, aminocarbonyloxy, aminosulfonyl,aminosulfonyloxy, aminosulfonylamino, amidino, aryl, substituted aryl,aryloxy, substituted aryloxy, arylthio, substituted arylthio, carboxyl,carboxyl ester, (carboxyl ester)amino, (carboxyl ester)oxy, cyano,cycloalkyl, substituted cycloalkyl, cycloalkyloxy, substitutedcycloalkyloxy, cycloalkylthio, substituted cycloalkylthio, cycloalkenyl,substituted cycloalkenyl, cycloalkenyloxy, substituted cycloalkenyloxy,cycloalkenylthio, substituted cycloalkenylthio, guanidino, substitutedguanidino, halo, hydroxy, heteroaryl, substituted heteroaryl,heteroaryloxy, substituted heteroaryloxy, heteroarylthio, substitutedheteroarylthio, heterocyclic, substituted heterocyclic, heterocyclyloxy,substituted heterocyclyloxy, heterocyclylthio, substitutedheterocyclylthio, nitro, SO₃H, substituted sulfonyl, sulfonyloxy,thioacyl, thiol, alkylthio, and substituted alkylthio, wherein saidsubstituents are defined herein.

“Aryloxy” refers to the group —O-aryl, where aryl is as defined herein,that includes, by way of example, phenoxy and naphthoxy.

“Substituted aryloxy” refers to the group —O-(substituted aryl) wheresubstituted aryl is as defined herein.

“Arylthio” refers to the group —S-aryl, where aryl is as defined herein.

“Substituted arylthio” refers to the group —S-(substituted aryl), wheresubstituted aryl is as defined herein.

“Carbonyl” refers to the divalent group —C(O)— which is equivalent to—C(═O)—.

“Carboxy” or “carboxyl” refers to —COOH or salts thereof.

“Carboxyl ester” or “carboxy ester” refers to the groups —C(O)O-alkyl,—C(O)O-substituted alkyl, —C(O)O-alkenyl, —C(O)O-substituted alkenyl,—C(O)O-alkynyl, —C(O)O-substituted alkynyl, —C(O)O-aryl,—C(O)O-substituted aryl, —C(O)O-cycloalkyl, —C(O)O-substitutedcycloalkyl, —C(O)O-cycloalkenyl, —C(O)O-substituted cycloalkenyl,—C(O)O-heteroaryl, —C(O)O-substituted heteroaryl, —C(O)O-heterocyclic,and —C(O)O-substituted heterocyclic wherein alkyl, substituted alkyl,alkenyl, substituted alkenyl, alkynyl, substituted alkynyl, cycloalkyl,substituted cycloalkyl, cycloalkenyl, substituted cycloalkenyl, aryl,substituted aryl, heteroaryl, substituted heteroaryl, heterocyclic, andsubstituted heterocyclic are as defined herein.

“(Carboxyl ester)amino” refers to the group —NR³⁸—C(O)O-alkyl,—NR³⁸—C(O)O-substituted alkyl, —NR³⁸—C(O)O-alkenyl,—NR³⁸—C(O)O-substituted alkenyl, —NR³⁸—C(O)O-alkynyl,—NR³⁸—C(O)O-substituted alkynyl, —NR³⁸—C(O)O-aryl,—NR³⁸—C(O)O-substituted aryl, —NR³⁸—C(O)O-cycloalkyl,—NR³⁸—C(O)O-substituted cycloalkyl, —NR³⁸—C(O)O-cycloalkenyl,—NR³⁸—C(O)O-substituted cycloalkenyl, —NR³⁸—C(O)O-heteroaryl,—NR³⁸—C(O)O-substituted heteroaryl, —NR³⁸—C(O)O-heterocyclic, and—NR³⁸—C(O)O-substituted heterocyclic wherein R³⁸ is alkyl or hydrogen,and wherein alkyl, substituted alkyl, alkenyl, substituted alkenyl,alkynyl, substituted alkynyl, cycloalkyl, substituted cycloalkyl,cycloalkenyl, substituted cycloalkenyl, aryl, substituted aryl,heteroaryl, substituted heteroaryl, heterocyclic, and substitutedheterocyclic are as defined herein.

“(Carboxyl ester)oxy” refers to the group —O—C(O)O-alkyl, substituted—O—C(O)O-alkyl, —O—C(O)O-alkenyl, —O—C(O)O-substituted alkenyl,—O—C(O)O-alkynyl, —O—C(O)O-substituted alkynyl, —O—C(O)O-aryl,—O—C(O)O-substituted aryl, —O—C(O)O-cycloalkyl, —O—C(O)O-substitutedcycloalkyl, —O—C(O)O-cycloalkenyl, —O—C(O)O-substituted cycloalkenyl,—O—C(O)O-heteroaryl, —O—C(O)O-substituted heteroaryl,—O—C(O)O-heterocyclic, and —O—C(O)O-substituted heterocyclic whereinalkyl, substituted alkyl, alkenyl, substituted alkenyl, alkynyl,substituted alkynyl, cycloalkyl, substituted cycloalkyl, cycloalkenyl,substituted cycloalkenyl, aryl, substituted aryl, heteroaryl,substituted heteroaryl, heterocyclic, and substituted heterocyclic areas defined herein.

“Cyano” refers to the group —CN.

“Cycloalkyl” refers to cyclic alkyl groups of from 3 to 10 carbon atomshaving single or multiple cyclic rings including fused, bridged, andspiro ring systems. One or more of the rings can be aryl, heteroaryl, orheterocyclic provided that the point of attachment is through thenon-aromatic, non-heterocyclic ring carbocyclic ring. Examples ofsuitable cycloalkyl groups include, for instance, adamantyl,cyclopropyl, cyclobutyl, cyclopentyl, and cyclooctyl. Other examples ofcycloalkyl groups include bicycle[2,2,2,]octanyl, norbornyl, andspirobicyclo groups such as spiro[4.5]dec-8-yl.

“Cycloalkenyl” refers to non-aromatic cyclic alkyl groups of from 3 to10 carbon atoms having single or multiple cyclic rings and having atleast one >C═C<ring unsaturation and preferably from 1 to 2 sitesof >C═C< ring unsaturation.

“Substituted cycloalkyl” and “substituted cycloalkenyl” refers to acycloalkyl or cycloalkenyl group having from 1 to 5 or preferably 1 to 3substituents selected from the group consisting of oxo, thione, alkyl,substituted alkyl, alkenyl, substituted alkenyl, alkynyl, substitutedalkynyl, alkoxy, substituted alkoxy, acyl, acylamino, acyloxy, amino,substituted amino, aminocarbonyl, aminothiocarbonyl, aminocarbonylamino,aminothiocarbonylamino, aminocarbonyloxy, aminosulfonyl,aminosulfonyloxy, aminosulfonylamino, amidino, aryl, substituted aryl,aryloxy, substituted aryloxy, arylthio, substituted arylthio, carboxyl,carboxyl ester, (carboxyl ester)amino, (carboxyl ester)oxy, cyano,cycloalkyl, substituted cycloalkyl, cycloalkyloxy, substitutedcycloalkyloxy, cycloalkylthio, substituted cycloalkylthio, cycloalkenyl,substituted cycloalkenyl, cycloalkenyloxy, substituted cycloalkenyloxy,cycloalkenylthio, substituted cycloalkenylthio, guanidino, substitutedguanidino, halo, hydroxy, heteroaryl, substituted heteroaryl,heteroaryloxy, substituted heteroaryloxy, heteroarylthio, substitutedheteroarylthio, heterocyclic, substituted heterocyclic, heterocyclyloxy,substituted heterocyclyloxy, heterocyclylthio, substitutedheterocyclylthio, nitro, SO₃H, substituted sulfonyl, sulfonyloxy,thioacyl, thiol, alkylthio, and substituted alkylthio, wherein saidsubstituents are defined herein.

“Cycloalkyloxy” refers to —O-cycloalkyl.

“Substituted cycloalkyloxy” refers to —O-(substituted cycloalkyl).

“Cycloalkylthio” refers to —S-cycloalkyl.

“Substituted cycloalkylthio” refers to —S-(substituted cycloalkyl).

“Cycloalkenyloxy” refers to —O-cycloalkenyl.

“Substituted cycloalkenyloxy” refers to —O-(substituted cycloalkenyl).

“Cycloalkenylthio” refers to —S-cycloalkenyl.

“Substituted cycloalkenylthio” refers to —S-(substituted cycloalkenyl).

“Guanidino” refers to the group —NHC(═NH)NH₂.

“Substituted guanidino” refers to —NR^(44C)(═NR⁴⁴)N(R⁴⁴)₂ where each R⁴⁴is independently selected from the group consisting of hydrogen, alkyl,substituted alkyl, aryl, substituted aryl, heteroaryl, substitutedheteroaryl, heterocyclic, and substituted heterocyclic and two R⁴⁴groups attached to a common guanidino nitrogen atom are optionallyjoined together with the nitrogen bound thereto to form a heterocyclicor substituted heterocyclic group, provided that at least one R⁴⁴ is nothydrogen, and wherein said substituents are as defined herein.

“Halo” or “halogen” refers to fluoro, chloro, bromo and iodo andpreferably is fluoro or chloro.

“Haloalkyl” refers to alkyl groups substituted with 1 to 5, 1 to 3, or 1to 2 halo groups, wherein alkyl and halo are as defined herein.

“Haloalkoxy” refers to alkoxy groups substituted with 1 to 5, 1 to 3, or1 to 2 halo groups, wherein alkoxy and halo are as defined herein.

“Haloalkylthio” refers to alkylthio groups substituted with 1 to 5, 1 to3, or 1 to 2 halo groups, wherein alkylthio and halo are as definedherein.

“Hydroxy” or “hydroxyl” refers to the group —OH.

“Heteroaryl” refers to an aromatic group of from 1 to 10 carbon atomsand 1 to 4 heteroatoms selected from the group consisting of oxygen,nitrogen and sulfur within the ring. Such heteroaryl groups can have asingle ring (e.g., pyridyl, pyridinyl or furyl) or multiple condensedrings (e.g., indolizinyl or benzothienyl) wherein the condensed ringsmay or may not be aromatic and/or contain a heteroatom provided that thepoint of attachment is through an atom of the aromatic heteroaryl group.In one embodiment, the nitrogen and/or the sulfur ring atom(s) of theheteroaryl group are optionally oxidized to provide for the N-oxide(N→O), sulfinyl, and/or sulfonyl moieties. Preferred heteroaryls includepyridinyl, pyrrolyl, indolyl, thiophenyl, and furanyl.

“Substituted heteroaryl” refers to heteroaryl groups that aresubstituted with from 1 to 5, preferably 1 to 3, or more preferably 1 to2 substituents selected from the group consisting of the same group ofsubstituents defined for substituted aryl.

“Heteroaryloxy” refers to —O-heteroaryl.

“Substituted heteroaryloxy” refers to the group —O-(substitutedheteroaryl).

“Heteroarylthio” refers to the group —S-heteroaryl.

“Substituted heteroarylthio” refers to the group —S-(substitutedheteroaryl).

“Heterocycle” or “heterocyclic” or “heterocycloalkyl” or “heterocyclyl”refers to a saturated or partially saturated, but not aromatic, grouphaving from 1 to 10 ring carbon atoms and from 1 to 4 ring heteroatomsselected from the group consisting of nitrogen, sulfur, or oxygen.Heterocycle encompasses single ring or multiple condensed rings,including fused bridged and spiro ring systems. In fused ring systems,one or more the rings can be cycloalkyl, aryl, or heteroaryl providedthat the point of attachment is through the non-aromatic heterocyclicring. In one embodiment, the nitrogen and/or sulfur atom(s) of theheterocyclic group are optionally oxidized to provide for the N-oxide,sulfinyl, and/or sulfonyl moieties.

“Substituted heterocyclic” or “substituted heterocycloalkyl” or“substituted heterocyclyl” refers to heterocyclyl groups that aresubstituted with from 1 to 5 or preferably 1 to 3 of the samesubstituents as defined for substituted cycloalkyl.

“Heterocyclyloxy” refers to the group —O-heterocycyl.

“Substituted heterocyclyloxy” refers to the group —O-(substitutedheterocycyl).

“Heterocyclylthio” refers to the group —S-heterocycyl.

“Substituted heterocyclylthio” refers to the group —S-(substitutedheterocycyl).

Examples of heterocycle and heteroaryls include, but are not limited to,azetidine, pyrrole, imidazole, pyrazole, pyridine, pyrazine, pyrimidine,pyridazine, indolizine, isoindole, indole, dihydroindole, indazole,purine, quinolizine, isoquinoline, quinoline, phthalazine,naphthylpyridine, quinoxaline, quinazoline, cinnoline, pteridine,carbazole, carboline, phenanthridine, acridine, phenanthroline,isothiazole, phenazine, isoxazole, phenoxazine, phenothiazine,imidazolidine, imidazoline, piperidine, piperazine, indoline,phthalimide, 1,2,3,4-tetrahydroisoquinoline,4,5,6,7-tetrahydrobenzo[b]thiophene, thiazole, thiazolidine, thiophene,benzo[b]thiophene, morpholinyl, thiomorpholinyl (also referred to asthiamorpholinyl), 1,1-dioxothiomorpholinyl, piperidinyl, pyrrolidine,and tetrahydrofuranyl.

“Nitro” refers to the group —NO₂.

“Oxo” refers to the atom (═O) or (—O⁻).

“Spiro ring systems” refers to bicyclic ring systems that have a singlering carbon atom common to both rings.

“Sulfonyl” refers to the divalent group —S(O)₂—.

“Substituted sulfonyl” refers to the group —SO₂-alkyl, —SO₂-substitutedalkyl, —SO₂-alkenyl, —SO₂-substituted alkenyl, —SO₂-cycloalkyl,—SO₂-substituted cycloalkyl, —SO₂-cycloalkenyl, —SO₂-substitutedcylcoalkenyl, —SO₂-aryl, —SO₂-substituted aryl, —SO₂-heteroaryl,—SO₂-substituted heteroaryl, —SO₂-heterocyclic, —SO₂-substitutedheterocyclic, wherein alkyl, substituted alkyl, alkenyl, substitutedalkenyl, alkynyl, substituted alkynyl, cycloalkyl, substitutedcycloalkyl, cycloalkenyl, substituted cycloalkenyl, aryl, substitutedaryl, heteroaryl, substituted heteroaryl, heterocyclic, and substitutedheterocyclic are as defined herein. Substituted sulfonyl includes groupssuch as methyl-SO₂—, phenyl-SO₂—, and 4-methylphenyl-SO₂—. The term“alkylsulfonyl” refers to —SO₂-alkyl. The term “haloalkylsulfonyl”refers to —SO₂-haloalkyl where haloalkyl is defined herein. The term“(substituted sulfonyl)amino” refers to —NH(substituted sulfonyl), andthe term “(substituted sulfonyl)aminocarbonyl” refers to—C(O)NH(substituted sulfonyl), wherein substituted sulfonyl is asdefined herein.

“Sulfonyloxy” refers to the group —OSO₂-alkyl, —OSO₂-substituted alkyl,—OSO₂-alkenyl, —OSO-substituted alkenyl, —OSO₂-cycloalkyl,—OSO₂-substituted cycloalkyl, —OSO₂-cycloalkenyl, —OSO₂-substitutedcylcoalkenyl, —OSO₂-aryl, —OSO₂-substituted aryl, —OSO₂-heteroaryl,—OSO₂-substituted heteroaryl, —OSO₂-heterocyclic, —OSO₂-substitutedheterocyclic, wherein alkyl, substituted alkyl, alkenyl, substitutedalkenyl, alkynyl, substituted alkynyl, cycloalkyl, substitutedcycloalkyl, cycloalkenyl, substituted cycloalkenyl, aryl, substitutedaryl, heteroaryl, substituted heteroaryl, heterocyclic, and substitutedheterocyclic are as defined herein.

“Thioacyl” refers to the groups H—C(S)—, alkyl-C(S)—, substitutedalkyl-C(S)—, alkenyl-C(S)—, substituted alkenyl-C(S)—, alkynyl-C(S)—,substituted alkynyl-C(S)—, cycloalkyl-C(S)—, substitutedcycloalkyl-C(S)—, cycloalkenyl-C(S)—, substituted cycloalkenyl-C(S)—,aryl-C(S)—, substituted aryl-C(S)—, heteroaryl-C(S)—, substitutedheteroaryl-C(S)—, heterocyclic-C(S)—, and substitutedheterocyclic-C(S)—, wherein alkyl, substituted alkyl, alkenyl,substituted alkenyl, alkynyl, substituted alkynyl, cycloalkyl,substituted cycloalkyl, cycloalkenyl, substituted cycloalkenyl, aryl,substituted aryl, heteroaryl, substituted heteroaryl, heterocyclic, andsubstituted heterocyclic are as defined herein.

“Thiol” refers to the group —SH.

“Thiocarbonyl” refers to the divalent group —C(S)— which is equivalentto —C(═S)—.

“Thione” refers to the atom (═S).

“Alkylthio” refers to the group —S-alkyl wherein alkyl is as definedherein.

“Substituted alkylthio” refers to the group —S— (substituted alkyl)wherein substituted alkyl is as defined herein.

“Compound” or “compounds” as used herein is meant to include thestereoiosmers and tautomers of the indicated formulas.

“Stereoisomer” or “stereoisomers” refer to compounds that differ in thechirality of one or more stereocenters. Stereoisomers includeenantiomers and diastereomers.

“Tautomer” refer to alternate forms of a compound that differ in theposition of a proton, such as enol-keto and imine-enamine tautomers, orthe tautomeric forms of heteroaryl groups containing a ring atomattached to both a ring —NH— moiety and a ring ═N-moiety such aspyrazoles, imidazoles, benzimidazoles, triazoles, and tetrazoles.

As used herein, the term “phosphate ester” refers to any one of themono-, di- or triphosphate esters of noribogaine, wherein the mono-, di-or triphosphate ester moiety is bonded to the 12-hydroxy group and/orthe indole nitrogen of noribogaine.

As used herein, the term “phosphate ester” refers to any one of themono-, di- or triphosphate esters of noribogaine, wherein the mono-, di-or triphosphate ester moiety is bonded to the 12-hydroxy group and/orthe indole nitrogen of noribogaine.

As used herein, the term “monophosphate” refers to the group —P(O)(OH)₂.

As used herein, the term “diphosphate” refers to the group—P(O)(OH)—OP(O)(OH)₂.

As used herein, the term “triphosphate” refers to the group—P(O)(OH)—(OP(O)(OH))₂OH.

As used herein, the term “ester” as it refers to esters of the mono-,di- or triphosphate group means esters of the monophosphate can berepresented by the formula —P(O)(OR⁴⁵)₂, where each R⁴⁵ is independentlyhydrogen, C₁-C₁₂ alkyl, C₃-C₁₀ cycloalkyl, C₆-C₁₄ aryl, heteroaryl of 1to 10 carbon atoms and 1 to 4 optionally oxidized heteroatoms selectedfrom the group consisting of oxygen, nitrogen, and sulfur and the like,provided that at least one R⁴⁵ is not hydrogen. Likewise, exemplaryesters of the di- or triphosphate can be represented by the formulas—P(O)(OR⁴⁵)—OP(O)(OR⁴⁵)₂ and —P(O)(OR⁴⁵)—(OP(O)(OR⁴⁵))₂OR⁴⁵, where R⁴⁵is as defined above.

As used herein, the term “hydrolyzable group” refers to a group that canbe hydrolyzed to release the free hydroxy group under hydrolysisconditions. Examples of hydrolysable group include, but are not limitedto those defined for R above. Preferred hydrolysable groups includecarboxyl esters, phosphates and phosphate esters. The hydrolysis may bedone by chemical reactions conditions such as base hydrolysis or acidhydrolysis or may be done in vivo by biological processes, such as thosecatalyzed by a phosphate hydrolysis enzyme. Nonlimiting examples ofhydrolysable group include groups linked with an ester-based linker(—C(O)O— or —OC(O)—), an amide-based linker (—C(O)NR⁴⁶— or —NR⁴⁶C(O)—),or a phosphate-linker (—P(O)(OR⁴⁶)—O—, —O—P(S)(OR⁴⁶)—O—,—O—P(S)(SR⁴⁶)—O—, —S—P(O)(OR⁴⁶)—O—, —O—P(O)(OR⁴⁶)—S—, —S—P(O)(OR⁴⁶)—S—,—O—P(S)(OR⁴⁶)—S—, —S—P(S)(OR⁴⁶)—O—, —O—P(O)(R⁴⁶)—O—, —O—P(S)(R⁴⁶)—O—,—S—P(O)(R⁴⁶)—O—, —S—P(S)(R⁴⁶)—O—, —S—P(O)(R⁴⁶)—S—, or —O—P(S)(R⁴⁶)—S—)where R⁴⁶ can be hydrogen or alkyl.

Substituted groups of this invention, as set forth above, do not includepolymers obtained by an infinite chain of substituted groups. At most,any substituted group can be substituted up to five times.

The term “iboga alkaloid” as used herein refers to ibogaine ornoribogaine. Iboga alkaloid also refers to a derivative of noribogaineor ibogaine, as well as pharmaceutically acceptable salts andpharmaceutically acceptable solvates thereof.

“Ibogaine” refers to the compound:

as well as ibogaine derivatives, pharmaceutically acceptable salts, andpharmaceutically acceptable solvates thereof. It should be understoodthat where “ibogaine” is mentioned herein, one more polymorphs ofibogaine can be utilized and are contemplated. Ibogaine is isolated fromTabernanth iboga, a shrub of West Africa. Ibogaine can also besynthesized using known methods. See, e.g., Büchi, et al. (1966), J. Am.Chem Society, 88(13), 3099-3109. Non-limiting examples of ibogainederivatives encompassed by this invention are given in more detail inthe “Compositions of the Invention” section below.

“Noribogaine” refers to the compound:

as well as noribogaine derivatives, pharmaceutically acceptable salts,and pharmaceutically acceptable solvates thereof. It should beunderstood that where “noribogaine” is mentioned herein, one morepolymorphs of noribogaine can be utilized and are contemplated. In someembodiments, noribogaine is noribogaine glucuronide. Noribogaine can beprepared by demethylation of naturally occurring ibogaine. Demethylationmay be accomplished by conventional techniques, such as by reaction withboron tribromide/methylene chloride at room temperature followed byconventional purification. See, for example, Huffman, et al., J. Org.Chem. 50:1460 (1985), which is incorporated herein by reference in itsentirety. Noribogaine can be synthesized as described, for example inU.S. Patent Pub. Nos. 2013/0165647, 2013/0303756, and 2012/0253037, PCTPatent Publication No. WO 2013/040471 (includes description of makingnoribogaine polymorphs), and U.S. patent application Ser. No.13/593,454, each of which is incorporated herein by reference in itsentirety.

“Noribogaine derivatives” refer to esters or O-carbamates ofnoribogaine, or pharmaceutically acceptable salts and/or solvates ofeach thereof. Also encompassed within this invention are derivatives ofnoribogaine that act as prodrug forms of noribogaine. A prodrug is apharmacological substance administered in an inactive (or significantlyless active) form. Once administered, the prodrug is metabolized in vivointo an active metabolite. Noribogaine derivatives include, withoutlimitation, those compounds set forth in U.S. Pat. Nos. 6,348,456 and8,362,007; as well as in U.S. patent application Ser. No. 13/165,626;and US Patent Application Publication Nos. US2013/0131046;US2013/0165647; US2013/0165425; and US2013/0165414; all of which areincorporated herein by reference. Non-limiting examples of noribogainederivatives encompassed by this invention are given in more detail inthe “Compositions of the Invention” section below.

This invention is not limited to any particular chemical form of ibogaalkaloid, and the drug may be given to patients either as a free base,solvate, or as a pharmaceutically acceptable acid addition salt. In thelatter case, the hydrochloride salt is generally preferred, but othersalts derived from organic or inorganic acids may also be used. Examplesof such acids include, without limitation, those described below as“pharmaceutically acceptable salts” and the like.

“Pharmaceutically acceptable composition” refers to a composition thatis suitable for administration to a human. Such compositions includevarious excipients, diluents, carriers, and such other inactive agentswell known to the skilled artisan.

“Pharmaceutically acceptable salt” refers to pharmaceutically acceptablesalts, including pharmaceutically acceptable partial salts, of acompound, which salts are derived from a variety of organic andinorganic counter ions well known in the art and include, by way ofexample only, hydrochloric acid, hydrobromic acid, phosphoric acid,sulfuric acid, methane sulfonic acid, phosphorous acid, nitric acid,perchloric acid, acetic acid, tartaric acid, lactic acid, succinic acid,citric acid, malic acid, maleic acid, aconitic acid, salicylic acid,thalic acid, embonic acid, enanthic acid, oxalic acid and the like, andwhen the molecule contains an acidic functionality, include, by way ofexample only, sodium, potassium, calcium, magnesium, ammonium,tetraalkylammonium, and the like.

“Therapeutically effective amount” or “effective amount” refers to anamount of a drug or an agent that, when administered to a patientsuffering from a condition, will have the intended therapeutic effect,e.g., alleviation, amelioration, palliation, elimination, or preventionof one or more manifestations (e.g., symptoms) of the condition in thepatient. The therapeutically effective amount will vary depending uponthe patient and the condition being treated, the weight and age of thesubject, the severity of the condition, the salt, solvate, or derivativeof the active drug portion chosen, the particular composition orexcipient chosen, the dosing regimen to be followed, timing ofadministration, the manner of administration and the like, all of whichcan be determined readily by one of ordinary skill in the art. The fulltherapeutic effect does not necessarily occur by administration of onedose, and may occur only after administration of a series of doses.Thus, a therapeutically effective amount may be administered in one ormore administrations. For example, and without limitation, atherapeutically effective amount of iboga alkaloid, in the context ofpotentiating the effect of an opioid analgesic, refers to an amount ofiboga alkaloid that increases the analgesic effect of the opioidanalgesic in a patient. This amount is also referred to as the“potentiating amount” of iboga alkaloid. In particular the potentiatingamount of the iboga alkaloid or pharmaceutically acceptable salt orsolvate thereof is such that the QT interval experienced by the patientis less than about 60 ms, less than about 50 ms, preferably less than 30ms, more preferably less than 20 ms.

A “therapeutic level” of a drug is an amount of iboga alkaloid orpharmaceutical salt and/or solvate thereof that is sufficient topotentiate the effect of an opioid analgesic, but not high enough topose any significant risk to the patient. Therapeutic levels of drugscan be determined by tests that measure the actual concentration of thecompound in the blood of the patient. This concentration is referred toas the “serum concentration.” Where the serum concentration of ibogaalkaloid is mentioned, it is to be understood that the term “ibogaalkaloid” encompasses any form of iboga alkaloid, including derivativesthereof.

The term “potentiation” as used herein refers to an increase in theaction of a drug by the addition of another drug that does notnecessarily possess similar properties.

The term “dose” refers to a range of iboga alkaloid or pharmaceuticalsalt or solvate thereof that provides a therapeutic serum level ofnoribogaine when given to a patient in need thereof. The dose is recitedin a range, for example from about 0.001 mg to about 50 mg per day, andcan be expressed either as milligrams (mg) or as mg/kg body weight. Theattending clinician will select an appropriate dose from the range basedon the patient's weight, age, opioid analgesic, health, and otherrelevant factors, all of which are well within the skill of the art.

The term “unit dose” refers to a dose of drug that is given to thepatient to provide therapeutic results, independent of the weight of thepatient. In such an instance, the unit dose is sold in a standard form(e.g., 10 mg tablet). The unit dose may be administered as a single doseor a series of subdoses. In some embodiments, the unit dose provides astandardized level of drug to the patient, independent of weight ofpatient. Many medications are sold based on a dose that is therapeuticto all patients based on a therapeutic window. In such cases, it is notnecessary to titrate the dosage amount based on the weight of thepatient.

“Treatment,” “treating,” and “treat” are defined as acting upon adisease, disorder, or condition with an agent to reduce or ameliorateharmful or any other undesired effects of the disease, disorder, orcondition and/or its symptoms. “Treatment,” as used herein, covers thetreatment of a human patient, and includes: (a) reducing the risk ofoccurrence of the condition in a patient determined to be predisposed tothe condition but not yet diagnosed as having the condition, (b)impeding the development of the condition, and/or (c) relieving thecondition, i.e., causing regression of the condition and/or relievingone or more symptoms of the condition. “Treating” or “treatment of” acondition or patient refers to taking steps to obtain beneficial ordesired results, including clinical results such as the reduction ofsymptoms. For purposes of this invention, beneficial or desired clinicalresults include, but are not limited to increasing the effect of a givendose of an opioid analgesic compound; reducing, attenuating, relieving,or reversing tolerance to the opioid analgesic; reducing the risk of orpreventing dependency and/or addiction to the opioid analgesic.

“Nociceptive pain” refers to pain that is sensed by nociceptors, whichare the nerves that sense and respond to parts of the body sufferingfrom a damage. The nociceptors can signal tissue irritation, impendinginjury, or actual injury. When activated, they transmit pain signals(via the peripheral nerves as well as the spinal cord) to the brain.Nociceptive pain is typically well localized, constant, and often has anaching or throbbing quality. A subtype of nociceptive pain includesvisceral pain and involves the internal organs. Visceral pain tends tobe episodic and poorly localized. Nociceptive pain may be time limited;when the tissue damage heals, the pain typically resolves. However,nociceptive pain related to arthritis or cancer may not be time limited.Nociceptive pain tends to respond to treatment with opiate analgesics,such as, for example, buprenorphin, codeine, hydrocodone, oxycodone,morphine, and the like. Examples of nociceptive pain include, withoutlimitation, pains from sprains, bone fractures, burns, bumps, bruises,cuts, inflammatory pain from an infection or arthritic disorder, painsfrom obstructions, cancer pain, and myofascial pain related to abnormalmuscle stresses.

“Neuropathic pain” refers to chronic pain, often due to tissue injury.Neuropathic pain is generally caused by injury or damage to nervefibers. It may include burning or coldness, “pins and needles”sensations, numbness and/or itching. It may be continuous and/orepisodic. Neuropathic pain is difficult to treat, but can be treatedwith opioids, including, without limitation, methadone, tramadol,tapentadol, oxycodone, methadone, morphine, levorphanol, and the like.Causes of neuropathic pain include, without limitation, alcoholism;amputation; back, leg, and hip problems; chemotherapy; diabetes; facialnerve problems; HIV/AIDS; multiple sclerosis; shingles; spine surgery;trigeminal neuralgia; fibromyalgia; and the like. In some cases, thecause of neuropathic pain may be unclear or unknown.

“Addictive” refers to a compound that, when administered to a mammalover a period of time, creates dependency and/or addiction in the mammalto that compound. The dependence can be physiological and/orpsychological. A therapeutic effect of an addictive compound on a mammalmay decrease with prolonged administration of the addictive compound,which is a non-limiting example of a physiological dependence. Whenadministered to a mammal, an addictive compound may also create acraving in the mammal for more of it, which is a non-limiting example ofa psychological dependence. Examples of addictive compounds include,without limitation, addictive opioids, and the like. In contrast,ibogaine, noribogaine, and derivatives of each are non-addictivealkaloids.

The term “tolerance” as used herein refers to the psychological and/orphysiologic process wherein the patient adjusts to the frequent presenceof a substance such that a higher dose of the substance is required toachieve the same effect. Tolerance may develop at different times fordifferent effects of the same drug (e.g., analgesic effect versus sideeffects). The mechanisms of tolerance are not entirely understood, butthey may include receptor down-regulation or desensitization, inhibitorypathway up-regulation, increased metabolism, and/or changes in receptorprocessing (e.g., phosphorylation).

“Opioid” refers to a natural product or derivative thereof containing abasic nitrogen atom, typically as part of a cyclic ring structure andless commonly as an acyclic moiety, and synthetic derivatives thereof.Opioids include compounds extracted from poppy pods and theirsemi-synthetic counterparts which bind to the opiate receptors.Non-limiting examples of opioids include, without limitation,buprenorphine, codeine, heroine, hydrocodone, oxycodone, morphine,hydromorphone, thebaine, and their derivatives, which will be well knownto the skilled artisan.

“Analgesic” and “analgesic agent” refer to a compound that is capable ofinhibiting and/or reducing pain in mammals. Pain may be inhibited and/orreduced in the mammal by the binding of the opioid analgesic agent tothe mu receptor. When analgesia is effected through the mu receptor, theanalgesic agent is referred to as a mu receptor agonist. Certainanalgesic agents are capable of inhibiting nociceptive and/orneuropathic pain including, by way of non-limiting example, morphine,codeine, hydromorphone, oxycodone, hydrocodone, buprenorphin, and thelike.

As used herein, the term “patient” refers to a human.

As used herein, the term “QT interval” refers to the measure of the timebetween the start of the Q wave and the end of the T wave in theelectrical cycle of the heart. Prolongation of the QT interval refers toan increase in the QT interval, i.e., increase from a baseline QTinterval.

A “pharmaceutically acceptable solvate” or “hydrate” of a compound ofthe invention means a solvate or hydrate complex that ispharmaceutically acceptable and that possesses the desiredpharmacological activity of the parent compound, and includes, but isnot limited to, complexes of a compound of the invention with one ormore solvent or water molecules, or 1 to about 100, or 1 to about 10, orone to about 2, 3 or 4, solvent or water molecules.

Herein the term solvate refers to a solid form of a compound thatcrystallizes with one or more molecules of solvent trapped inside. A fewexamples of solvents that can be used to create solvates, such aspharmaceutically acceptable solvates, include, but are not limited to,water, methanol, ethanol, isopropanol, butanol, C1-C6 alcohols ingeneral (and optionally substituted), tetrahydrofuran, acetone, ethyleneglycol, propylene glycol, acetic acid, formic acid, water, and solventmixtures thereof. Other such biocompatible solvents which may aid inmaking a pharmaceutically acceptable solvate are well known in the artand applicable to the present invention. Additionally, various organicand inorganic acids and bases can be added or even used alone as thesolvent to create a desired solvate. Such acids and bases are known inthe art. When the solvent is water, the solvate can be referred to as ahydrate. Further, by being left in the atmosphere or recrystallized, thecompounds of the present invention may absorb moisture, may include oneor more molecules of water in the formed crystal, and thus become ahydrate. Even when such hydrates are formed, they are included in theterm “solvate”. Solvate also is meant to include such compositions whereanother compound or complex co-crystallizes with the compound ofinterest.

As used herein the term “abuse liability” refers to the properties of adrug (e.g., an opiate) that would lead to abuse and dependence inhumans. The drug may be available as a prescription medication and/orthrough illicit routes.

II. Compositions of the Invention

As will be apparent to the skilled artisan upon reading this disclosure,this invention provides compositions for potentiating the effect of anopioid analgesic in a patient undergoing or planning to undergo opioidanalgesic treatment for pain, comprising an effective amount of an ibogaalkaloid, derivative, prodrug, pharmaceutically acceptable salt and/orsolvate of each thereof and wherein the iboga alkaloid is dosed in anamount to both potentiate the opioid while maintaining an acceptable QTinterval prolongation. In a preferred embodiment, the iboga alkaloid isnoribogaine or a salt or solvate thereof.

In some embodiments, the composition is formulated for oral,transdermal, internal, pulmonary, rectal, nasal, vaginal, lingual,intravenous, intraarterial, intramuscular, intraperitoneal,intracutaneous or subcutaneous delivery.

In one embodiment, the therapeutically effective amount of the compoundis from about 0.001 mg to about 50 mg per day. In a preferredembodiment, the therapeutically effective amount of the compound is fromabout 0.001 mg to about 30 mg per day. In another embodiment, thetherapeutically effective amount of the compound is from about 0.001 mgto about 20 mg per day. In another embodiment, the therapeuticallyeffective amount of the compound is from about 0.001 mg to about 10 mgper day. In another embodiment, the therapeutically effective amount ofthe compound is from about 0.001 mg to about 5 mg per day. In anotherembodiment, the therapeutically effective amount of the compound is fromabout 0.001 mg to about 1 mg per day. In another embodiment, thetherapeutically effective amount of the compound is from about 0.001 mgto about 0.1 mg per day. In another embodiment, the therapeuticallyeffective amount of the compound is from about 0.001 mg to about 0.01 mgper day. The ranges include both extremes as well as any subranges therebetween.

In another embodiment, the therapeutically effective amount of thecompound is from about 0.01 mg to about 50 mg per day. In anotherembodiment, the therapeutically effective amount of the compound is fromabout 0.01 mg to about 30 mg per day. In another embodiment, thetherapeutically effective amount of the compound is from about 0.01 mgto about 20 mg per day. In another embodiment, the therapeuticallyeffective amount of the compound is from about 0.01 mg to about 10 mgper day. In another embodiment, the therapeutically effective amount ofthe compound is from about 0.01 mg to about 5 mg per day. In anotherembodiment, the therapeutically effective amount of the compound is fromabout 0.01 mg to about 1 mg per day. In another embodiment, thetherapeutically effective amount of the compound is from about 0.01 mgto about 0.1 mg per day. The ranges include both extremes as well as anysubranges there between. The ranges include both extremes as well as anysubranges there between.

In another embodiment, the therapeutically effective amount of thecompound is from about 0.1 mg to about 50 mg per day. In anotherembodiment, the therapeutically effective amount of the compound is fromabout 0.1 mg to about 30 mg per day. In another embodiment, thetherapeutically effective amount of the compound is from about 0.1 mg toabout 20 mg per day. In another embodiment, the therapeuticallyeffective amount of the compound is from about 0.1 mg to about 10 mg perday. In another embodiment, the therapeutically effective amount of thecompound is from about 0.1 mg to about 5 mg per day. In anotherembodiment, the therapeutically effective amount of the compound is fromabout 0.1 mg to about 1 mg per day. The ranges include both extremes aswell as any subranges there between. The ranges include both extremes aswell as any subranges there between.

In another embodiment, the therapeutically effective amount of thecompound is from about 1 mg to about 50 mg per day. In anotherembodiment, the therapeutically effective amount of the compound is fromabout 1 mg to about 30 mg per day. In another embodiment, thetherapeutically effective amount of the compound is from about 1 mg toabout 20 mg per day. In another embodiment, the therapeuticallyeffective amount of the compound is from about 1 mg to about 10 mg perday. In another embodiment, the therapeutically effective amount of thecompound is from about 1 mg to about 5 mg per day. The ranges includeboth extremes as well as any subranges there between. The ranges includeboth extremes as well as any subranges there between.

In one embodiment, the therapeutically effective amount of the compoundis from about 5 mg to about 50 mg per day. In a preferred embodiment,the therapeutically effective amount of the compound is from about 5 mgto about 30 mg per day. In another embodiment, the therapeuticallyeffective amount of the compound is from about 5 mg to about 20 mg perday. In another embodiment, the therapeutically effective amount of thecompound is from about 10 mg to about 50 mg per day. In anotherembodiment, the therapeutically effective amount of the compound is fromabout 10 mg to about 30 mg per day. In another embodiment, thetherapeutically effective amount of the compound is from about 10 mg toabout 20 mg per day. The ranges include both extremes as well as anysubranges there between.

In one embodiment, the therapeutically effective amount of the compoundis about 0.001 mg per day. In one embodiment, the therapeuticallyeffective amount of the compound is about 0.01 mg per day. In oneembodiment, the therapeutically effective amount of the compound isabout 0.1 mg per day. In one embodiment, the therapeutically effectiveamount of the compound is about 1 mg per day. In one embodiment, thetherapeutically effective amount of the compound is about 5 mg per day.In one embodiment, the therapeutically effective amount of the compoundis about 10 mg per day. In one embodiment, the therapeutically effectiveamount of the compound is about 15 mg per day. In one embodiment, thetherapeutically effective amount of the compound is about 20 mg per day.In one embodiment, the therapeutically effective amount of the compoundis about 25 mg per day. In one embodiment, the therapeutically effectiveamount of the compound is about 30 mg per day. In one embodiment, thetherapeutically effective amount of the compound is about 35 mg per day.In one embodiment, the therapeutically effective amount of the compoundis about 40 mg per day. In one embodiment, the therapeutically effectiveamount of the compound is about 45 mg per day. In one embodiment, thetherapeutically effective amount of the compound is about 50 mg per day.In one embodiment, the therapeutically effective amount of the compoundis about 60 mg per day. In one embodiment, the therapeutically effectiveamount of the compound is about 70 mg per day. In one embodiment, thetherapeutically effective amount of the compound is about 80 mg per day.

In one embodiment, the iboga alkaloid is ibogaine, noribogaine, anibogaine derivative, noribogaine derivative, or prodrug, salt or solvatethereof.

In one embodiment, the noribogaine derivative is represented by FormulaI:

or a pharmaceutically acceptable salt and/or solvate thereof,wherein R is hydrogen or a hydrolyzable group such as hydrolyzableesters of from about 1 to 12 carbons.

Generally, in the above formula, R is hydrogen or a group of theformula:

wherein X is a C₁-C₁₂ group, which is unsubstituted or substituted. Forexample, X may be a linear alkyl group such as methyl, ethyl, n-propyl,n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl,n-undecyl or n-dodecyl, or a branched alkyl group, such as i-propyl orsec-butyl. Also, X may be a phenyl group or benzyl group, either ofwhich may be substituted with lower alkyl groups or lower alkoxy groups.Generally, the lower alkyl and/or alkoxy groups have from 1 to about 6carbons. For example, the group R may be acetyl, propionyl or benzoyl.However, these groups are only exemplary.

Generally, for all groups X, they may either be unsubstituted orsubstituted with lower alkyl or lower alkoxy groups. For example,substituted X may be o-, m- or p-methyl or methoxy benzyl groups.

C₁-C₁₂ groups include C₁-C₁₂ alkyl, C₃-C₁₂ cycloalkyl, C₆-C₁₂ aryl,C₇-C₁₂ arylalkyl, wherein C_(x), indicates that the group contains xcarbon atoms. Lower alkyl refers to C₁-C₄ alkyl and lower alkoxy refersto C₁-C₄ alkoxy.

In one embodiment, the noribogaine derivative is represented by FormulaII:

or a pharmaceutically acceptable salt and/or solvate thereof,wherein

-   -   is a single or double bond;    -   R¹ is halo, OR², or C₁-C₁₂ alkyl optionally substituted with 1        to 5 R¹⁰;    -   R² is hydrogen or a hydrolysable group selected from the group        consisting of —C(O)R^(x), —C(O)OR^(x) and —C(O)N(R^(y))₂ where        each R^(x) is selected from the group consisting of C₁-C₆ alkyl        optionally substituted with 1 to 5 R¹⁰, and each R^(y) is        independently selected from the group consisting of hydrogen,        C₁-C₆ alkyl optionally substituted with 1 to 5 R¹⁰, C₆-C₁₄ aryl        optionally substituted with 1 to 5 R¹⁰, C₃-C₁₀ cycloalkyl        optionally substituted with 1 to 5 R¹⁰, C₁-C₁₀ heteroaryl having        1 to 4 heteroatoms and which is optionally substituted with 1 to        5 R¹⁰, C₁-C₁₀ heterocyclic having 1 to 4 heteroatoms and which        is optionally substituted with 1 to 5 R¹⁰, and where each R^(y),        together with the nitrogen atom bound thereto form a C₁-C₆        heterocyclic having 1 to 4 heteroatoms and which is optionally        substituted with 1 to 5 R¹⁰ or a C₁-C₆ heteroaryl having 1 to 4        heteroatoms and which is optionally substituted with 1 to 5 R¹⁰;    -   R³ is selected from the group consisting of hydrogen, C₁-C₁₂        alkyl optionally substituted with 1 to 5 R¹⁰, aryl optionally        substituted with 1 to 5 R¹⁰, —C(O)R⁶, —C(O)NR⁶R⁶ and —C(O)OR⁶;    -   R⁴ is selected from the group consisting of hydrogen,        —(CH₂)_(m)OR⁸, —CR⁷(OH)R⁸, —(CH₂)_(m)CN, —(CH₂)_(m)COR⁸,        —(CH₂)_(m)CO₂R⁸, —(CH₂)_(m)C(O)NR⁷R⁸, —(CH₂)_(m)C(O)NR⁷NR⁸R⁸,        —(CH₂)_(m)C(O)NR⁷NR⁸C(O)R⁹, and —(CH₂)_(m)NR⁷R⁸;    -   m is 0, 1, or 2;    -   L is a bond or C₁-C₁₂ alkylene;    -   R⁵ is selected from the group consisting of hydrogen, C₁-C₁₂        alkyl substituted with 1 to 5 R¹⁰, C₁-C₁₂ alkenyl substituted        with 1 to 5 R¹⁰, —X¹—R⁷, —(X¹—Y)_(n)—X¹—R⁷, —SO₂NR⁷R⁸,        —O—C(O)R⁹, —C(O)OR⁸, —C(O)NR⁷R⁸, —NR⁷R⁸, —NHC(O)R⁹, and        —NR⁷C(O)R⁹;    -   each R⁶ is independently selected from the group consisting of        hydrogen, C₁-C₁₂ alkyl, C₂-C₁₂ alkenyl, C₂-C₁₂ alkynyl, C₆-C₁₀        aryl, C₁-C₆ heteroaryl having 1 to 4 heteroatoms, and C₁-C₆        heterocycle having 1 to 4 heteroatoms, and wherein the alkyl,        alkenyl, alkynyl, aryl, heteroaryl, and heterocycle are        optionally substituted with 1 to R¹⁰;    -   X¹ is selected from the group consisting of O and S;    -   Y is C₁-C₄ alkylene or C₆-C₁₀ arylene, or a combination thereof;    -   n is 1, 2, or 3;    -   R⁷ and R⁸ are each independently selected from the group        consisting of hydrogen, C₁-C₁₂ alkyl optionally substituted with        1 to 5 R¹⁰, C₁-C₆ heterocycle having 1 to 4 heteroatoms and        which is optionally substituted with 1 to 5R¹⁰, C₃-C₁₀        cycloalkyl optionally substituted with 1 to 5 R¹⁰, C₆-C₁₀ aryl        optionally substituted with 1 to 5 R¹⁰ and C₁-C₆ heteroaryl        having 1 to 4 heteroatoms optionally substituted with 1 to 5        R¹⁰;    -   R⁹ is selected from the group consisting of C₁-C₁₂ alkyl        optionally substituted with 1 to 5 R¹⁰, C₁-C₆ heterocycle having        1 to 4 heteroatoms optionally substituted with 1 to 5 R¹⁰,        C₃-C₁₀ cycloalkyl optionally substituted with 1 to 5 R¹⁰, C₆-C₁₀        aryl optionally substituted with 1 to 5 R¹⁰ and C₁-C₆ heteroaryl        having 1 to 4 heteroatoms optionally substituted with 1 to 5        R¹⁰;    -   R¹⁰ is selected from the group consisting of C₁-C₄ alkyl,        phenyl, halo, —OR¹¹, CN, —COR¹¹¹, —CO₂R¹¹, —C(O)NHR¹¹, —NR¹¹R¹¹,        —C(O)NR¹¹R¹¹, —C(O)NHN HR¹¹, —C(O)NR¹¹NHR¹¹, —C(O)NR¹¹NR¹¹R¹¹,        —C(O)NHNR¹¹C(O)R¹¹, —C(O)NHNHC(O)R¹¹, —SO₂NR¹¹R¹¹,        —C(O)NR¹¹NR¹¹C(O)R¹¹, and —C(O)NR¹¹NHC(O)R¹¹; and    -   R¹¹ is independently hydrogen or C₁-C₁₂ alkyl;    -   provided that:    -   when L is a bond, then R⁵ is not hydrogen;    -   when        is a double bond, R¹ is an ester hydrolyzable group, R³ and R⁴        are both hydrogen, then -L-R⁵ is not ethyl;    -   when        is a double bond, R¹ is —OH, halo or C₁-C₁₂ alkyl optionally        substituted with 1 to 5 R¹⁰, then R⁴ is hydrogen; and    -   when        is a double bond, R¹ is OR², R⁴ is hydrogen, -L-R⁵ is ethyl,        then R² is not a hydrolyzable group selected from the group        consisting of an ester, amide, carbonate and carbamate.

In one embodiment, the noribogaine derivative is represented by FormulaIII:

or a pharmaceutically acceptable salt and/or solvate thereof,wherein

-   -   is a single or double bond;    -   R¹² is halo, —OH, —SH, —NH₂, —S(O)₂N(R¹⁷)₂, —R^(z)-L¹-R¹⁸,        —R^(z)-L¹-R¹⁹,—R^(z)-L¹-R²⁰, —R    -   L¹ is alkylene, arylene, —C(O)-alkylene, —C(O)-arylene,        —C(O)O-arylene, —C(O)O— alkylene, —C(O)NR²⁰-alkylene,        —C(O)NR²⁰-arylene, —C(NR²⁰)NR²⁰-alkylene or        —C(NR²⁰)NR²⁰-arylene, wherein L¹ is configured such that        —O-L¹-R¹⁸ is —OC(O)-alkylene-R¹⁸, —OC(O)O-arylene-R¹⁸,        —OC(O)O-alkylene-R¹⁸, —OC(O)-arylene-R¹⁸,        —OC(O)NR²⁰-alkylene-R¹⁸, —OC(O)NR²⁰-arylene-R¹⁸,        —OC(NR²⁰)NR²⁰-alkylene-R¹⁸ or —OC(NR²⁰)NR²⁰-arylene-R¹⁸, and        wherein the alkylene and arylene are optionally substituted with        1 to 2 R¹⁶;    -   R^(—)is hydrogen, —S(O)₂OR²⁰, —S(O)₂R²⁰, —C(O)R¹⁵, —C(O)NR¹⁵R¹⁵,        —C(O)OR¹⁵, C₁-C₁₂ alkyl optionally substituted with 1 to 5 R¹⁶,        C₁-C₁₂ alkenyl optionally substituted with 1 to 5 R¹⁶, or aryl        optionally substituted with 1 to 5 R¹⁶; R¹⁴ is hydrogen, halo,        —OR′, —CN, C₁-C₁₂ alkyl, C₁-C₁₂ alkoxy, aryl or aryloxy, where        the alkyl, alkoxy, aryl, and aryloxy are optionally substituted        with 1 to 5 R¹⁶;    -   each R¹⁵ is independently selected from the group consisting of        hydrogen, C₁-C₁₂ alkyl, C₂-C₁₂ alkenyl, C₂-C₁₂ alkynyl, aryl,        heteroaryl, and heterocycle, and wherein the alkyl, alkenyl,        alkynyl, aryl, heteroaryl, and heterocycle are optionally        substituted with 1 to 5 R¹⁶;    -   R¹⁶ is selected from the group consisting of phenyl, halo, —OR′,        —CN, —COR¹⁷, —CO₂R¹⁷, —NR¹⁷R¹⁷, —NR¹⁷C(O)R¹⁷, —NR¹⁷SO₂R¹⁷,        —C(O)NR¹⁷R¹⁷, —C(O)NR¹⁷NR¹⁷R¹⁷, —SO₂NR¹⁷R¹⁷ and        —C(O)NR¹⁷NR¹⁷C(O)R¹⁷;    -   each R¹⁷ is independently hydrogen or C₁-C₁₂ alkyl optionally        substituted with from 1 to 3 halo;    -   R¹⁸ is hydrogen, —C(O)R²⁰, —C(O)OR²⁰, —C(O)N(R²⁰)₂ or        —N(R²⁰)C(O)R²⁰;    -   R¹⁹ is hydrogen, —N(R²⁰)₂, —C(O)N(R²⁰)₂, —C(NR²⁰)N(R²⁰)₂,        —C(NSO₂R²⁰)N(R²⁰)₂, —NR²⁰C(O) N(R²⁰)₂, —NR²⁰C(S)N(R²⁰)₂,        —NR²⁰C(NR²⁰)N(R²⁰)₂, —NR²⁰C(NSO₂R²⁰)N(R²⁰)₂ or tetrazole; and    -   each R²⁰ is independently selected from the group consisting of        hydrogen, C₁-C₁₂ alkyl and aryl;    -   provided that:    -   when        is a double bond and R^(—)and R¹⁴ are hydrogen, then R¹² is not        hydroxy;    -   when        is a double bond, R¹⁴ is hydrogen, R¹² is —O-L¹-R¹⁸, —O-L¹-R¹⁹,        —O-L¹-R²⁰, and L¹ is alkylene, then —O-L¹-R¹⁸, —O-L¹-R¹⁹,        —O-L¹-R²⁰ are not methoxy;    -   when        is a double bond, R¹⁴ is hydrogen, R^(z) is O, L¹ is        —C(O)-alkylene, —C(O)-arylene, —C(O)O-arylene, —C(O)O-alkylene,        —C(O)NR²⁰-alkylene, or —C(O)NR²⁰-arylene, then none of R¹⁸, R¹⁹        or R²⁰ are hydrogen.

In one embodiment, the noribogaine derivative is represented by FormulaIV:

or a pharmaceutically acceptable salt and/or solvate thereof,

wherein

R²¹ is selected from the group consisting of hydrogen, a hydrolysablegroup selected from the group consisting of —C(O)R²³, —C(O)NR²⁴R²⁵ and—C(O)OR²⁶, where R²³ is selected from the group consisting of hydrogen,alkyl, substituted alkyl, alkenyl, substituted alkenyl, alkynyl andsubstituted alkynyl, R²⁴ and R²⁵ are independently selected from thegroup consisting of hydrogen, alkyl, substituted alkyl, alkenyl,substituted alkenyl, alkynyl, substituted alkynyl, aryl, substitutedaryl, heteroaryl, substituted heteroaryl, heterocyclic and substitutedheterocyclic, R²⁶ is selected from the group consisting of alkyl,substituted alkyl, alkenyl, substituted alkenyl, alkynyl, substitutedalkynyl, aryl, substituted aryl, heteroaryl, substituted heteroaryl,heterocyclic and substituted heterocyclic, provided that R²¹ is not asaccharide or an oligosaccharide;

L² is selected from the group consisting of a covalent bond and acleavable linker group;

R²² is selected from the group consisting of hydrogen, alkyl,substituted alkyl, alkenyl, substituted alkenyl, alkynyl, substitutedalkynyl, aryl, substituted aryl, cycloalkyl, substituted cycloalkyl,heteroaryl, substituted heteroaryl, heterocyclic, and substitutedheterocyclic, provided that R is not a saccharide or an oligosaccharide;

provided that when L² is a covalent bond and R²² is hydrogen, then R²¹is selected from the group consisting of —C(O)NR²⁴R²⁵ and —C(O)OR²⁶; and

further provided that when R²¹ is hydrogen or —C(O)R²³ and L² is acovalent bond, then R²² is not hydrogen.

In one embodiment, the noribogaine derivative is represented by FormulaV:

or a pharmaceutically acceptable salt and/or solvate thereof,wherein:

refers to a single or a double bond provided that when

is a single bond, Formula V refers to the corresponding dihydrocompound;

R²⁷ is hydrogen or SO₂OR²⁹;

R²⁸ is hydrogen or SO₂OR²⁹;

R²⁹ is hydrogen or C₁-C₆ alkyl;

provided that at least one of R²⁷ and R²⁸ is not hydrogen.

In one embodiment, the noribogaine derivative is represented by FormulaVI:

or a pharmaceutically acceptable salt and/or solvate thereof,wherein:

refers to a single or a double bond provided that when

is a single bond, Formula VI refers to the corresponding vicinal dihydrocompound;

R³⁰ is hydrogen, a monophosphate, a diphosphate or a triphosphate; and

R³¹ is hydrogen, a monophosphate, a diphosphate or a triphosphate;

provided that both R³⁰ and R³¹ are not hydrogen;

wherein one or more of the monophosphate, diphosphate and triphosphategroups of R³⁰ and R³¹ are optionally esterified with one or more C₁-C₆alkyl esters.

In some embodiments, the ibogaine or ibogaine derivative is representedby Formula VII:

or a pharmaceutically acceptable salt and/or solvate thereof,wherein

-   -   R¹⁰⁰ is H, halo, C₁-C₃ alkyl, substituted C₁-C₃ alkyl, OR¹¹⁰,        NH₂, NHR¹¹⁰, NR¹¹⁰R¹¹¹, NHC(O)R¹¹⁰, or NR¹¹⁰C(O)R¹¹¹;    -   R¹⁰¹ is H, C₁-C₃ alkyl, substituted C₁-C₃ alkyl, C₁-C₃ alkoxy,        CH₂—X—CH₃, or (CH₂)_(m)R¹⁰³;    -   R¹⁰² is H, COOH, COOR¹⁰⁴, (CH₂)_(n)OH, CH(OH)R¹⁰⁵, CH₂OR¹⁰⁵,        C(O)NH₂, C(O)NHR¹⁰⁵, C(O)NR¹⁰⁵R¹⁰⁶, C(O)NHNH₂, C(O)NHNHR¹⁰⁵,        C(O)NHNR¹⁰⁵R¹⁰⁶, C(O)NR¹⁰⁵NH₂, C(O)NR¹⁰⁵NHR¹⁰⁶,        C(O)NR¹⁰⁵NR¹⁰⁶R¹⁰⁷, C(O)NHNH(C(O)R¹⁰⁵), C(O)NHNR¹⁰⁵(C(O)R¹⁰⁶),        C(O)NR¹⁰⁵NH(C(O)R¹⁰⁶), C(O)NR¹⁰⁵NR¹⁰⁶(C(O)R¹⁰⁷), CN, or        C(O)R¹⁰⁵;    -   R¹⁰³ is C₁-C₃ alkyl, benzyl, substituted C₁-C₃ alkyl, YH, YR¹⁰⁸,        YC(O)R¹⁰⁸, C(O)YR¹⁰⁸, C(O)NH₂, C(O)NHR¹⁰⁸, C(O)NR¹⁰⁸R¹⁰⁹, NH¹⁰⁸,        NHR¹⁰⁹, NR¹⁰⁸R¹⁰⁹, NHC(O)R¹⁰⁸, O(CH₂)_(p)O(CH₂)_(q)O(CH₂)_(r)CH₃        or NR¹⁰⁸C(O)R¹⁰⁹; R¹⁰⁴ is C₁-C₆ alkyl or (CH₂CH₂O)_(n)CH₃;    -   R¹⁰⁵, R¹⁰⁶, R¹⁰⁷, R¹⁰⁸, R¹⁰⁹, R¹¹⁰ and R¹¹¹ are independently        alkyl or substituted alkyl;    -   R¹¹² is H, alkyl, or substituted alkyl;    -   R¹¹³ is H, OR¹¹⁰, alkyl, or substituted alkyl;    -   X is O or NH;    -   Y is O or S;    -   m is an integer selected from 0-8;    -   each of n, p and q is 1, 2 or 3; and    -   r is 0, 1 or 2.

In some embodiments, the ibogaine or ibogaine derivative is representedby Formula VIII:

or a pharmaceutically acceptable salt and/or solvate thereof,wherein

R¹⁰⁰ is hydrogen or C₁-C₃ alkoxy,

-   -   R¹⁰¹ is hydrogen, C₁-C₃ alkyl, C₁-C₃ alkoxy,        (CH₂)_(m)OC(O)alkyl, (CH₂)_(m)OH, (CH₂)_(m)Oalkyl,        (CH₂)_(m)O(CH₂)_(p)O(CH₂)_(q)O(CH₂)_(r)CH₃ or CH₂—Y—CH₃ where        each of m, p and q is 1, 2 or 3; and r is 0, 1 or 2, Y is O or        NH, and    -   R¹⁰² is H, (CH₂)_(n)OH, COOH, or COOR¹⁰⁴, where R¹⁰⁴ is C₁-C₆        alkyl or (CH₂CH₂O)_(n)CH₃, where n is 1, 2, or 3.

In one embodiment, R¹⁰⁰ is methoxy. In one embodiment, R¹⁰¹ is ethyl. Inone embodiment, R¹⁰¹ is methoxy. In one embodiment, R¹⁰¹ is CH₂—Y—CH₃where Y is O. In one embodiment, R¹⁰¹ is CH₂—Y—CH₃ where Y is NH. In oneembodiment, R¹⁰² is hydrogen. In one embodiment, In one embodiment, R¹⁰²is COOR¹⁰⁴ and R¹⁰⁴ is methyl. In one embodiment, n=1. In a preferredembodiment, R¹⁰⁰, R¹⁰¹ and R¹⁰² are all not hydrogen. In one embodiment,when R¹⁰⁰ is methoxy and R¹⁰¹ is hydrogen, then R¹⁰² is COOH or COOR¹⁰⁴.In another embodiment, when R¹⁰⁰ is methoxy and R¹⁰¹ is hydrogen, then Xis COOR¹⁰⁴ where R¹⁰⁴ is (CH₂CH₂O)CH₃.

In one embodiment, R¹⁰² is hydrogen.

In one embodiment, R¹⁰¹ is H. In one embodiment, R¹⁰¹ is C₁-C₃ alkyl,such as ethyl. In one embodiment, R¹⁰¹ is CH₂CH₂OH. In one embodiment,R¹⁰¹ is CH₂CH₂OCH₃. In one embodiment, R¹⁰¹ is CH₂CH₂OCH₂Ph. In oneembodiment, R¹⁰¹ is CH₂CH₂OC(O)alkyl. In one embodiment, R¹⁰¹ isCH₂CH₂O(CH₂)_(p)O(CH₂)_(q)O(CH₂)_(r)CH₃.

In one embodiment, R¹⁰² is CH₂OH and CH(OH)R¹⁰⁵. In one embodiment, R¹⁰²is CH₂OR¹⁰⁵. In one embodiment, R¹⁰² is CO₂R¹⁰⁵. In one embodiment, R¹⁰²is C(O)NH₂, C(O)NHR¹⁰⁵, or C(O)NR¹⁰⁵R¹⁰⁶. In one embodiment, R¹⁰² isC(O)NHNH₂, C(O)NHNHR¹⁰⁵, C(O)NR¹⁰⁵NH₂, C(O)NHNR¹⁰⁵R¹⁰⁶,C(O)NHR¹⁰⁵NHR¹⁰⁶, or C(O)NR¹⁰⁵NR¹⁰⁶R¹⁰⁷. In one embodiment, R¹⁰² isC(O)NHNH(C(O)R¹⁰⁵), C(O)NHNR¹⁰⁵(C(O)R¹⁰⁶), C(O)NR¹⁰⁵NH(C(O)R¹⁰⁶), orC(O)NR¹⁰⁵NR¹⁰⁶(C(O)R¹⁰⁷). In one embodiment, R¹⁰² is C(O)R¹⁰⁵.

In some embodiments, the ibogaine or ibogaine derivative is selectedfrom:

Name Structure coronaridine

18-hydroxycoronaridine

18-methoxycoronaridine

18-benzyloxycoronaridine

18-hydroxycoronaridine laurate

18-hydroxycoronaridine methoxyethoxymethyl ether

18-hydroxycoronaridine acetate

voacangine

18-hydroxyvoacangine

18-methoxyvoacangine

18-benzyloxyvoacangine

18-hydroxyvoacangine laurate

18-hydroxyvoacangine acetate

18-hydroxyvoacangine methoxyethoxymethyl ether

conopharyngine

18-hydroxyconopharyngine

18-methoxyconopharyngine

18-benzyloxyconopharyngine

18-hydroxyconopharyngine laurate

18-hydroxyconopharyngine acetate

18-hydroxyconopharyngine methoxyethoxymethyl ether

ibogamine

16-ethoxycarbonyl-18- hydroxyibogamine

16-hydroxymethyl-18- hydroxyibogamine

16-ethoxycarbonyl-18- methoxyibogamine

16-hydroxymethyl-18- methoxyibogamine

16-ethoxycarbonyl-18- benzyloxyibogamine

16-ethoxycarbonyl-18- hydroxyibogamine laurate

16-ethoxycarbonyl-18- hydroxyibogamine acetate

16-ethoxycarbonyl-18- hydroxyibogamine methoxyethoxymethyl ether

ibogaine

16-ethoxycarbonyl-18- hydroxyibogaine

16-hydroxymethyl-18- hydroxyibogaine

16-ethoxycarbonyl-18- methoxyibogaine

16-hydroxymethyl-18- methoxyibogaine

16-ethoxycarbonyl-18- benzyloxyibogaine

16-ethoxycarbonyl-18- hydroxyibogaine laurate

16-ethoxycarbonyl-18- hydroxyibogaine acetate

16-ethoxycarbonyl-18- hydroxyibogaine methoxyethoxymethyl ether

ibogaline

16-ethoxycarbonyl-18- hydroxyibogaline

16-hydroxymethyl-18- hydroxyibogaline

16-ethoxycarbonyl-18- methoxyibogaline

16-hydroxymethyl-18- methoxyibogaline

16-ethoxycarbonyl-18- benzyloxyibogaline

16-ethoxycarbonyl-18- hydroxyibogaline laurate

16-ethoxycarbonyl-18- hydroxyibogaline acetate

16-ethoxycarbonyl-18- hydroxyibogaline methoxyethoxymethyl ether

and pharmaceutically acceptable salts and/or solvates thereof.

In one embodiment, the ibogaine derivative is:

III. Methods of the Invention

As will be apparent to the skilled artisan upon reading this disclosure,the present invention provides a method for potentiating the effect ofan opioid analgesic in a patient undergoing or planning to undergoopioid analgesic therapy, comprising administering to the patient adosage of iboga alkaloid or pharmaceutically acceptable salt and/orsolvate thereof wherein the iboga alkaloid is dosed in an amount topotentiate the opioid while maintaining an acceptable QT intervalprolongation.

In one aspect, the patient is naïve with respect to opioid treatment.That is, the patient has not been administered an opioid analgesic for aperiod of time such that any residual opioid in the blood stream is lessthan an amount to impart an analgesic effect to the patient. In oneaspect, the patient has not been administered an opioid analgesic withintwo weeks and preferably within four weeks prior to administration ofiboga alkaloid in combination with an opioid analgesic. It is to beunderstood that such a time period may differ based on the opioid,characteristics of the patient, and the like, and is readily determinedby the skilled clinician.

In one aspect of this invention, a patient is treated with an addictiveopioid analgesic to relieve the patient's pain. The pain may be of anytype and from any source. In one embodiment, the patient is treated foracute pain. In one embodiment, the patient is treated for chronic pain.In one embodiment, the patient is treated for nociceptive pain. In oneembodiment, the patient is treated for neuropathic pain. In someembodiments, the pain is caused by surgery, diabetes, trigeminalneuralgia, fibromyalgia, cancer, central pain syndrome, tissue damage,physical injury, and the like. In some embodiments, the source of thepain is unknown or unclear.

In one aspect of this invention, there is provided a method forpotentiating the analgesic effect of an opioid analgesic in a patientundergoing or planning to undergo opioid analgesic therapy, the methodcomprising administering a potentiating amount of an iboga alkaloid orpharmaceutically acceptable salt and/or solvate thereof to potentiatethe effect of the opioid as an analgesic, wherein the iboga alkaloid isdosed in an amount to potentiate the opioid while maintaining anacceptable QT interval. In particular, the potentiating amount of theiboga alkaloid or pharmaceutically acceptable salt or solvate thereof issuch that the QT interval prolongation experienced by the patient isless than about 60 ms, less than about 50 ms, preferably less than 30ms, more preferably less than 20 ms.

In one embodiment, maximum QT interval as a result of iboga alkaloidtreatment is less than about 500 ms, less than about 490 ms, less thanabout 480 ms, less than about 470 ms, less than about 460 ms, less thanabout 450 ms, less than about 440 ms, or less than about 430 ms.

In one aspect of this invention, there is provided a method for reducingtolerance to an opioid analgesic in a patient who exhibits tolerance toan opioid during opioid analgesic therapy, the method comprisingadministering an effective amount of an iboga alkaloid orpharmaceutically acceptable salt and/or solvate thereof to reducetolerance to the opioid, wherein the iboga alkaloid is dosed in anamount to potentiate the opioid while maintaining an acceptable QTinterval and/or QT interval prolongation.

In one aspect of this invention, there is provided a method forpreventing dependence on an opioid analgesic in a patient undergoing orplanning to undergo opioid analgesic therapy, the method comprisingadministering an effective amount of an iboga alkaloid orpharmaceutically acceptable salt and/or solvate thereof to preventdependence on the opioid, wherein the iboga alkaloid is dosed in anamount to potentiate the opioid while maintaining an acceptable QTinterval and/or QT interval prolongation.

In one aspect of this invention, there is provided a method forinhibiting addiction to an opioid analgesic in a patient undergoing orplanning to undergo opioid analgesic therapy, the method comprisingadministering an effective amount of an iboga alkaloid orpharmaceutically acceptable salt and/or solvate thereof to preventaddiction to the opioid, wherein the iboga alkaloid is dosed in anamount to potentiate the opioid while maintaining an acceptable QTinterval and/or QT interval prolongation.

In one aspect, this disclosure relates to a method for maintainingefficacy of an opioid analgesic in a patient, the method comprisingperiodically administering to the patient an opioid and an initialamount of noribogaine for a period of time, determining whether thepatient exhibits tolerance to the opioid, and increasing the amount ofnoribogaine administered without increasing the amount of opioidadministered when the patient exhibits tolerance to the opioid. In oneembodiment, the amount of noribogaine is increased after a predeterminedperiod of time.

In one aspect, this disclosure relates to a method for maintainingefficacy of an opioid analgesic in a patient, the method comprisingperiodically administering to the patient an opioid and noribogaine fora period of time, determining whether the patient exhibits tolerance tothe opioid, and increasing the amount of opioid administered with orwithout increasing the amount of norbogaine administered when thepatient exhibits tolerance to the opioid. In one embodiment, the amountof opioid and/or noribogaine is increased after a predetermined periodof time.

In one aspect, this disclosure relates to a method for determining theamount of noribogaine required for potentiation of an opioid byevaluating tolerance to the opioid and the amount of opioid administeredto a patient.

In one aspect, this disclosure relates to a method for determining theamount of opioid required to be administered to a patient in order tohave an analgesic effect, when the opioid is to be administered afteradministration of noribogaine.

In one aspect, this disclosure relates to a method to decreaserespiratory depression in a patient by an opioid analgesic byco-administering noribogaine to reduce the amount of opioid required tobe administered to the patient.

As used herein, “preventing” or “reducing” tolerance includes increasingthe amount of time to opioid tolerance (i.e., the duration of opioidtreatment before tolerance occurs); increasing the dose of opioid atwhich tolerance occurs; and/or preventing tolerance from occurring atany duration or dose of opioid administration.

As used herein, “preventing” or “reducing” dependence includesincreasing the amount of time to opioid dependence (i.e., the durationof opioid treatment before dependence occurs); increasing the dose ofopioid at which dependence occurs; and/or preventing dependence fromoccurring at any duration or dose of opioid administration.

The efficacy of a particular amount of an opioid analgesic to treat pain(have an analgesic effect) in a patient can be measured by a variety ofwell-known methods. These include, for example, animal studies toprovide an objective measure (e.g., tail flick assay, foot splay assay),as well as pain screening instruments (e.g., Brief Pain Inventory,Likert Scale, McGill Pain Questionnaire, Patient Global Impression ofChange and Clinical Global Impression of Change, the Short Form-36Quality of Life Questionnaire scores, the Profile of Mood States, or theRoland Morris Disability Scale); Pain Assessment and Documentation Tool(e.g., to monitor on-going pain assessment); and other methodswell-known in the art.

Tolerance or development of tolerance to an opioid can be measured byany method known in the art, now or in the future. For example, theIntracranial Self-Stimulation (ICSS) is a test of tolerance in rodents.In humans, tests such as the cold pressor test or experimental heat painmay be administered before and after treatment with analgesic todetermine tolerance and/or efficacy. Differences in the patientscreening instruments may also be used for this purpose. Similarly,dependence or development of dependence may be determined by any methodknown in the art, now or in the future.

In some embodiments, the amount of opioid and/or noribogaineadministered to the patient is titrated over time, for example based onthe opioid analgesic administered, the amount of pain experienced by thepatient (before and/or after opioid administration), the amount oftolerance and/or dependence experienced by the patient, genetic factors(likelihood of dependence or tolerance to an opioid analgesic, optimalopioid analgesic for the patient, etc.), length of time the opioid hasbeen administered to the patient, length of time the opioid is expectedto be administered to the patient, duration of noribogaine treatment(actual or expected), and the like. Such titration is within theabilities of the skilled clinician.

In one embodiment, the QT interval is not prolonged more than about 60ms. In one embodiment, the QT interval is not prolonged more than about50 ms. In one embodiment, the QT interval is not prolonged more thanabout 30 ms. In a preferred embodiment, the QT interval is not prolongedmore than about 20 ms. In one embodiment, the QT interval is notprolonged more than about 15 ms. In an especially preferred embodiment,the QT interval is not prolonged more than about 10 ms.

In one embodiment, the average serum concentration of the iboga alkaloidis less than about 150 ng/mL. In one embodiment, the average serumconcentration of the iboga alkaloid is less than about 100 ng/mL. In apreferred embodiment, the average serum concentration of the ibogaalkaloid is less than about 50 ng/mL. In one embodiment, the averageserum concentration of the iboga alkaloid is less than about 20 ng/mL.In one embodiment, the average serum concentration of the iboga alkaloidis less than about 10 ng/mL. The ranges include extremes as well as anysubranges.

In one embodiment, the serum concentration is less than about 10,000ng*hour/mL (area under the curve for a period of time, AUC/t) over theperiod during which the iboga alkaloid is administered. In a preferredembodiment, the serum concentration is less than about 8,000 ng*hour/mL(AUC/t) over the period during which the iboga alkaloid is administered.In one embodiment, the serum concentration is less than about 6,000ng*hour/mL (AUC/t) over the period during which the iboga alkaloid isadministered. The ranges include extremes as well as any subranges.

In another embodiment, a unit dose of iboga alkaloid or salt or solvatethereof is administered. In one embodiment, the unit dose comprisesabout 0.001 mg to about 80 mg iboga alkaloid per day. In one embodiment,the unit dose comprises about 0.001 mg to about 50 mg iboga alkaloid perday. In one embodiment, the unit dose comprises about 0.001 mg to about30 mg iboga alkaloid per day. In one embodiment, the unit dose comprisesabout 0.001 mg to about 20 mg iboga alkaloid per day. In one embodiment,the unit dose comprises about 0.01 mg to about 50 mg iboga alkaloid perday. In one embodiment, the unit dose comprises about 0.01 mg to about60 mg iboga alkaloid per day. In one embodiment, the unit dose comprisesabout 0.01 mg to about 70 mg iboga alkaloid per day. In one embodiment,the unit dose comprises about 0.01 mg to about 80 mg iboga alkaloid perday. In one embodiment, the unit dose comprises about 0.01 mg to about30 mg iboga alkaloid per day. In one embodiment, the unit dose comprisesabout 0.01 mg to about 20 mg iboga alkaloid per day. The ranges includeextremes as well as any subranges. In one embodiment, the unit dosefurther comprises an opioid analgesic. It is to be understood that theterm “unit dose” means a dose sufficient to provide therapeutic resultswhether given all at once or serially over a period of time.

In some embodiments, the amount of iboga alkaloid administered isindependent of the amount of opioid administered. In some embodiments,the amount of iboga alkaloid administered is dependent on the amount ofopioid administered. In one embodiment, the iboga alkaloid to opioidratio is between about 100:1 and about 1:100. In one embodiment, theiboga alkaloid to opioid ratio is between about 100:1 and about 1:90. Inone embodiment, the iboga alkaloid to opioid ratio is between about100:1 and about 1:80. In one embodiment, the iboga alkaloid to opioidratio is between about 100:1 and about 1:70. In one embodiment, theiboga alkaloid to opioid ratio is between about 100:1 and about 1:60. Inone embodiment, the iboga alkaloid to opioid ratio is between about100:1 and about 1:50. In one embodiment, the iboga alkaloid to opioidratio is between about 100:1 and about 1:40. In one embodiment, theiboga alkaloid to opioid ratio is between about 100:1 and about 1:30. Inone embodiment, the iboga alkaloid to opioid ratio is between about100:1 and about 1:10. In one embodiment, the iboga alkaloid to opioidratio is between about 100:1 and about 1:1. In one embodiment, the ibogaalkaloid to opioid ratio is between about 10:1 and about 1:100. In oneembodiment, the iboga alkaloid to opioid ratio is between about 10:1 andabout 1:90. In one embodiment, the iboga alkaloid to opioid ratio isbetween about 10:1 and about 1:80. In one embodiment, the iboga alkaloidto opioid ratio is between about 10:1 and about 1:70. In one embodiment,the iboga alkaloid to opioid ratio is between about 10:1 and about 1:60.In one embodiment, the iboga alkaloid to opioid ratio is between about10:1 and about 1:50. In one embodiment, the iboga alkaloid to opioidratio is between about 10:1 and about 1:40. In one embodiment, the ibogaalkaloid to opioid ratio is between about 10:1 and about 1:30. In oneembodiment, the iboga alkaloid to opioid ratio is between about 10:1 andabout 1:20. In a preferred embodiment, the iboga alkaloid to opioidratio is between about 10:1 and about 1:10. In one embodiment, the ibogaalkaloid to opioid ratio is between about 10:1 and about 1:1. The rangesinclude extremes as well as any subranges.

In some embodiments, the patient is administered periodically, such asonce, twice, three times, four times or five times daily with the ibogaalkaloid or a pharmaceutically acceptable salt and/or solvate thereof.In some embodiments, the administration is once daily, or once everysecond day, once every third day, three times a week, twice a week, oronce a week. The iboga alkaloid may be administered concurrently with orproximate in time to administration of the opioid analgesic. The dosageand frequency of the administration depends on the route ofadministration, dosage, age, and body weight of the patient, conditionof the patient, opioid analgesic, length of time of analgesic treatment,and the like, without limitation. Determination of dosage and frequencysuitable for the present technology can be readily made a qualifiedclinician.

In some embodiments, it is contemplated that an increase in the amountof iboga alkaloid administered may be required during treatment. In oneembodiment, the amount of iboga alkaloid administered to the patientchanges over time. In one embodiment, the amount of iboga alkaloid isincreased by about 1% to about 400% at some time after the ibogaalkaloid treatment commences. In one embodiment, the amount of ibogaalkaloid is increased by about 0.001 mg, 0.01 mg, 0.1 mg, 1 mg, 5 mg,about 10 mg, about 20 mg, or about 30 mg at some time after the ibogaalkaloid treatment commences. In one embodiment, the increased dose isincremental, i.e., the dose of iboga alkaloid is increased gradually(incrementally) over time. In one embodiment the incremental or gradientincrease of iboga alkaloid is administered with a concomitantincremental or gradient decrease of opioid analgesic. For example, theopioid analgesic can be the sole medicament provided to the patient andover time the amount of iboga alkaloid is introduced while concomitantlyreducing the amount of opioid analgesic. In one embodiment, the dose ofiboga alkaloid is increased all at once. In one embodiment, the dose ofiboga alkaloid varies (up and down) during treatment. In one embodiment,the increased amount of iboga alkaloid administered to the patient doesnot exceed about 80 mg per day. In a preferred embodiment, the increasedamount of iboga alkaloid administered to the patient does not exceedabout 50 mg per day.

In one aspect, the amount of iboga alkaloid administered per day isincreased between one day and about two weeks after iboga alkaloidtreatment commences. In one embodiment, the amount of iboga alkaloidadministered per day is increased about one week to about two weeksafter iboga alkaloid treatment commences. In one embodiment, the amountof iboga alkaloid administered per day is increased about 3 days afteriboga alkaloid treatment commences. In one embodiment, the amount ofiboga alkaloid administered per day is increased about 4 days afteriboga alkaloid treatment commences. In one embodiment, the amount ofiboga alkaloid administered per day is increased about 5 days afteriboga alkaloid treatment commences. In one embodiment, the amount ofiboga alkaloid administered per day is increased about 6 days afteriboga alkaloid treatment commences. In one embodiment, the amount ofiboga alkaloid administered per day is increased about one week afteriboga alkaloid treatment commences. In one embodiment, the amount ofiboga alkaloid administered per day is increased about 10 days afteriboga alkaloid treatment commences. In one embodiment, the amount ofiboga alkaloid administered per day is increased about 2 weeks afteriboga alkaloid treatment commences.

In one embodiment, the amount of iboga alkaloid administered per day isfurther increased between two days and about two weeks after the firstincrease (or an increase subsequent to the first increase). In oneembodiment, the amount of iboga alkaloid administered per day isincreased about 2 days after the first increase (or a subsequentincrease). In one embodiment, the amount of iboga alkaloid administeredper day is increased about 4 days after the first increase (or asubsequent increase). In one embodiment, the amount of iboga alkaloidadministered per day is increased about 5 days after the first increase(or a subsequent increase). In one embodiment, the amount of ibogaalkaloid administered per day is increased about 6 days after the firstincrease (or a subsequent increase). In one embodiment, the amount ofiboga alkaloid administered per day is increased about 1 week after thefirst increase (or a subsequent increase). In one embodiment, the amountof iboga alkaloid administered per day is increased about 10 days afterthe first increase (or a subsequent increase). In one embodiment, theamount of iboga alkaloid administered per day is increased about 2 weeksafter the first increase (or a subsequent increase).

It is further contemplated that less opioid analgesic will be requiredto treat pain when the patient is being administered the iboga alkaloid.For example, between about 25% and about 75% of the original or usualopioid dose can be administered to a patient. The “usual” opioid doserefers to the dose that would be prescribed by the clinician for theamount and type of pain in the patient, and may depend on a variety ofother factors (e.g., size, weight, sex, and/or health of the patient tobe treated). In one embodiment, between about 25% and about 65% of theoriginal or usual opioid dose is administered. In one embodiment,between about 25% and about 50% of the original or usual opioid dose isadministered. In one embodiment, between about 35% and about 75% of theoriginal or usual opioid dose is administered. In one embodiment,between about 45% and about 75% of the original or usual opioid dose isadministered. In one embodiment, between about 50% and about 75% of theoriginal or usual opioid dose is administered. The ranges includeextremes as well as any subranges.

It is understood that patients receiving treatment with an ibogaalkaloid may exhibit different (i.e., patient-specific) levels oftolerance to the iboga alkaloid and/or opioid analgesic. As such,patients may be monitored during all or some duration of theadministration period by a skilled clinican to ensure the iboga alkaloidand/or opioid analgesic is dosed in an amount to potentiate the opioidwhile maintaining an acceptable QT interval prolongation and without aresultant respiratory depression. During treatment with the ibogaalkaloid, the opioid analgesic may require an adjustment up or down.Such adjustments are easily determined by the skilled clinician, basedon the patient's needs.

In a preferred embodiment, the iboga alkaloid is administered for aperiod of time, and then stopped. In one embodiment, the iboga alkaloidis administered for about 2 weeks to about 5 weeks before stopping. Inone embodiment, the iboga alkaloid is administered for about 2 weeksbefore stopping. In one embodiment, the iboga alkaloid is administeredfor about 10 days before stopping. In one embodiment, the iboga alkaloidis administered for about 3 weeks before stopping. In one embodiment,the iboga alkaloid is administered for about 4 weeks before stopping. Inone embodiment, the iboga alkaloid is administered for about 5 weeksbefore stopping. In one embodiment, the opioid analgesic is administeredto the patient after the iboga alkaloid administration is stopped. Inone embodiment, administration of the opioid analgesic ceases atapproximately the same time that administration of the iboga alkaloid isstopped.

Some patients, for example those with acute pain, may not need torestart iboga alkaloid administration. For example, such patients maydiscontinue opioid use after a short time. Other patients, particularlythose receiving long-term analgesic treatment, may restart ibogaalkaloid administration.

In one embodiment, the iboga alkaloid is administered for a subsequentperiod of time after a break in administration. In one embodiment, thebreak in administration lasts between 2 days and about 3 weeks. In oneembodiment, the break in administration lasts between 1 week and about 3weeks. In one embodiment, the break in administration lasts between 2weeks and about 3 weeks. The subsequent period of time may be the sameamount of time as the previous amount of time, or longer or shorter. Inone embodiment, the iboga alkaloid is administered for a subsequentperiod of time, and then stopped. In one embodiment, the amount ofopioid analgesic administered to the patient is increased during thebreak. In one embodiment, the amount of opioid analgesic is notincreased during the break. When the amount of opioid analgesicadministered to the patient is increased during the break, that amountis preferably decreased once iboga alkaloid administration is restarted.

Iboga alkaloid or a pharmaceutically acceptable salt and/or solvatethereof, suitable for administration in accordance with the methodsprovide herein, can be suitable for a variety of delivery modesincluding, without limitation, oral and transdermal delivery.Compositions suitable for internal, pulmonary, rectal, nasal, vaginal,lingual, intravenous, intra-arterial, intramuscular, intraperitoneal,intracutaneous and subcutaneous routes may also be used. Possible dosageforms include tablets, capsules, pills, powders, aerosols,suppositories, parenterals, and oral liquids, including suspensions,solutions and emulsions. Sustained release dosage forms may also beused. All dosage forms may be prepared using methods that are standardin the art (see e.g., Remington's Pharmaceutical Sciences, 16th ed., A.Oslo editor, Easton Pa. 1980).

In one embodiment, the iboga alkaloid and opioid are administered in thesame composition (e.g., unit dose). It is contemplated thatadministration using the same composition will increase patientcompliance with respect to iboga alkaloid administration. It is furthercontemplated that compositions comprising an opioid analgesic incombination with an iboga alkaloid will deter or prevent abuse of theopioid, e.g., by an opioid-addicted individual. The individual may bethe patient or a different individual.

In one embodiment, the iboga alkaloid and opioid are administered indifferent compositions. It is contemplated that administration asseparate doses allows for more personalized dosing of the ibogaalkaloid. Separate dosings is especially appropriate in a clinicalsetting (e.g., inpatient setting), where patient compliance is not anissue and/or where individualized therapy is important.

As would be understood by one of skill in the art, the opioid analgesicdose is dependent on multiple factors, including the size/weight of thepatient; type of pain to be treated; opioid analgesic used; health ofthe patient; other medications being administered to the patient; degreeof tolerance, dependence, or addiction to the opioid; and the like. Inone embodiment, the opioid dose is within those considered safe andeffective in the art, for example as described in the Agency MedicalDirectors' Group 2010 Opioid Dosing Guideline (accessible atwww.agencymeddirectors.wa.gov/opioiddosing.asp). Proper opioid dosingcan be determined by the skilled clinician.

In one embodiment, potentiation of the effect of the opioid analgesic bythe iboga alkaloid results in a lower dosage prescribed for the patient,and/or reduced or delayed need for increases in the opioid dose. Forexample, the patient may require no increase in the opioid dose, asmaller incremental increase in the opioid dose, and/or a longer time tosuch an increase than without iboga alkaloid administration.

In one embodiment, the iboga alkaloid is noribogaine or a noribogainederivative as described herein, or a pharmaceutically acceptable saltand/or solvate thereof. In one embodiment, the iboga alkaloid isibogaine or an ibogaine derivative as described herein, or apharmaceutically acceptable salt and/or solvate thereof.

In a preferred embodiment, iboga alkaloid or a pharmaceuticallyacceptable salt and/or solvate thereof is administered orally, which mayconveniently be provided in tablet, caplet, sublingual, liquid orcapsule form. In certain embodiments, the iboga alkaloid is provided asthe HCL salt of the iboga alkaloid (e.g., noribogaine HCl), with dosagesreported as the amount of free base iboga alkaloid. In some embodiments,the iboga alkaloid HCl is provided in hard gelatin capsules containingonly iboga alkaloid HCl with no excipients. In some embodiments, thecapsule further comprises an opioid analgesic.

The patient may be receiving any addictive opioid analgesic for thetreatment of pain. In a preferred embodiment, the opioid analgesic isselected from the group consisting of fentanyl, hydrocodone,hydromorphone, morphine, oxycodone, buprenorphine, codeine, heroin,thebaine, buprenorphine, methadone, meperidine, tramadol, tapentadol,levorphanol, sufentanil, pentazocine, oxymorphone, and derivatives ofeach thereof.

Unit Dose and Kit of Parts

One aspect of this invention is directed to a unit dose of an ibogaalkaloid for the potentiation of the effect of an opioid analgesic,wherein the unit dose comprises a composition comprising an ibogaalkaloid or salt and/or solvate thereof, wherein the iboga alkaloid isdosed in an amount to potentiate the opioid while maintaining anacceptable QT interval prolongation. In a preferred embodiment, the unitdose further comprises an opioid analgesic.

In one aspect is provided a kit of parts for potentiation of theanalgesic effect of an opioid analgesic, wherein the kit comprises acomposition comprising an iboga alkaloid or salt and/or solvate thereofand a means for administering the composition to a patient in needthereof. In a preferred embodiment, the kit of parts further comprisesan opioid analgesic. In a preferred embodiment, the opioid analgesic isprovided in the same composition (e.g., unit dose) as the ibogaalkaloid. In one embodiment, the opioid analgesic is provided in aseparate composition from the iboga alkaloid. The means foradministration to a patient can include, for example, any one orcombination of noribogaine, or a noribogaine derivative, or apharmaceutically acceptable salt and/or solvate thereof, a transdermalpatch, a syringe, a needle, an IV bag comprising the composition, a vialcomprising the composition, an inhaler comprising the composition, etc.In one embodiment, the kit of parts further comprises instructions fordosing and/or administration of the composition.

In some embodiments, the kit of parts includes a composition comprisingiboga alkaloid and opioid analgesic at a ratio between about 100:1 andabout 1:100. In one embodiment, the iboga alkaloid to opioid ratio isbetween about 100:1 and about 1:90. In one embodiment, the ibogaalkaloid to opioid ratio is between about 100:1 and about 1:80. In oneembodiment, the iboga alkaloid to opioid ratio is between about 100:1and about 1:70. In one embodiment, the iboga alkaloid to opioid ratio isbetween about 100:1 and about 1:60. In one embodiment, the ibogaalkaloid to opioid ratio is between about 100:1 and about 1:50. In oneembodiment, the iboga alkaloid to opioid ratio is between about 100:1and about 1:40. In one embodiment, the iboga alkaloid to opioid ratio isbetween about 100:1 and about 1:30. In one embodiment, the ibogaalkaloid to opioid ratio is between about 100:1 and about 1:10. In oneembodiment, the iboga alkaloid to opioid ratio is between about 100:1and about 1:1. In one embodiment, the iboga alkaloid to opioid ratio isbetween about 10:1 and about 1:100. In one embodiment, the ibogaalkaloid to opioid ratio is between about 10:1 and about 1:90. In oneembodiment, the iboga alkaloid to opioid ratio is between about 10:1 andabout 1:80. In one embodiment, the iboga alkaloid to opioid ratio isbetween about 10:1 and about 1:70. In one embodiment, the iboga alkaloidto opioid ratio is between about 10:1 and about 1:60. In one embodiment,the iboga alkaloid to opioid ratio is between about 10:1 and about 1:50.In one embodiment, the iboga alkaloid to opioid ratio is between about10:1 and about 1:40. In one embodiment, the iboga alkaloid to opioidratio is between about 10:1 and about 1:30. In one embodiment, the ibogaalkaloid to opioid ratio is between about 10:1 and about 1:20. In apreferred embodiment, the iboga alkaloid to opioid ratio is betweenabout 10:1 and about 1:10. In one embodiment, the iboga alkaloid toopioid ratio is between about 10:1 and about 1:1. The ranges includeextremes as well as any subranges.

The composition may include opioid analgesic at any amount. For example,in some embodiments, the composition comprises about 1 mg to about 250mg opioid analgesic. Preferably, the composition comprises about 5 mg toabout 250 mg opioid analgesic. As would be understood by one skilled inthe art, the amount of opioid analgesic in the composition is dependenton the opioid analgesic, as well as other considerations (e.g., weightof patient, age, tolerance to or dependence on an opioid, degree ofpain, and the like).

In some aspects, the invention is directed to a kit of parts foradministration of the composition (i.e., iboga alkaloid and/or opioid),the kit comprising multiple delivery vehicles, wherein each deliveryvehicle contains a discrete amount of iboga alkaloid or pharmaceuticallyacceptable salt and/or solvate thereof, and optionally an opioidanalgesic, and further wherein each delivery vehicle is identified bythe amount of iboga alkaloid and/or opioid provided therein; andoptionally further comprising a dosing treatment schedule in a readablemedium. In some embodiments, the dosing treatment schedule includes theamount of iboga alkaloid required to potentiate the action of a givenopioid and/or to achieve a target serum level. In some embodiments, thekit of parts includes a dosing treatment schedule that provides anattending clinician the ability to select a dosing regimen of ibogaalkaloid based on criteria such as, without limitation, the opioidanalgesic administered, sex of the patient, mass of the patient, and theserum level that the clinician desires to achieve. In some embodiments,the dosing treatment schedule further provides information correspondingto the volume of blood in a patient based upon weight (or mass) and sexof the patient. In an embodiment, the storage medium can include anaccompanying pamphlet or similar written information that accompaniesthe unit dose form in the kit. In an embodiment, the storage medium caninclude electronic, optical, or other data storage, such as anon-volatile memory, for example, to store a digitally-encodedmachine-readable representation of such information.

The term “delivery vehicle” as used herein refers to any formulationthat can be used for administration of iboga alkaloid orpharmaceutically acceptable salt and/or solvate thereof to a patient.The delivery vehicle optionally comprises an opioid analgesic.Non-limiting, exemplary delivery vehicles include caplets, pills,capsules, tablets, powder, liquid, or any other form by which the drugcan be administered. Delivery vehicles may be intended foradministration by oral, inhaled, injected, or any other means.

The term “readable medium” as used herein refers to a representation ofdata that can be read, for example, by a human or by a machine.Non-limiting examples of human-readable formats include pamphlets,inserts, or other written forms. Non-limiting examples ofmachine-readable formats include any mechanism that provides (i.e.,stores and/or transmits) information in a form readable by a machine(e.g., a computer, tablet, and/or smartphone). For example, amachine-readable medium includes read-only memory (ROM); random accessmemory (RAM); magnetic disk storage media; optical storage media; andflash memory devices. In one embodiment, the machine-readable medium isa CD-ROM. In one embodiment, the machine-readable medium is a USB drive.In one embodiment, the machine-readable medium is a Quick Response Code(QR Code) or other matrix barcode.

In some aspects, the machine-readable medium comprises software thatcontains information regarding dosing schedules for the unit dose formof iboga alkaloid or pharmaceutically acceptable salt and/or solvatethereof, and optionally other drug information. In some embodiments, thesoftware may be interactive, such that the attending clinician or othermedical professional can enter patient information. In a non-limitingexample, the medical professional may enter the weight and sex of thepatient to be treated, and the software program provides a recommendeddosing regimen based on the information entered. The amount and timingof iboga alkaloid recommended to be delivered will be within the dosagesas provided herein, and/or those that result in the serum concentrationsas provided herein.

In some embodiments, the kit of parts comprises multiple deliveryvehicles in a variety of dosing options. For example, the kit of partsmay comprise pills or tablets in multiple dosages of iboga alkaloid orpharmaceutically acceptable salt and/or solvate thereof and/or opioidanalgesic per pill. Each pill is labeled such that the medicalprofessional and/or patient can easily distinguish different dosages.Labeling may be based on printing or embossing on the pill, shape of thepill, color of pill, the location of the pill in a separate, labeledcompartment within the kit, and/or any other distinguishing features ofthe pill. In some embodiments, all of the delivery vehicles within a kitare intended for one patient. In some embodiments, the delivery vehicleswithin a kit are intended for multiple patients.

One aspect of this invention is directed to a kit of parts for thepotentiation of the analgesic effect of an opioid analgesic in a patientundergoing or planning to undergo opioid analgesic therapy, wherein thekit comprises a unit dose form of iboga alkaloid or salt and/or solvatethereof. The unit dose form provides a patient with an average serumlevel of iboga alkaloid of less than about 80 ng/mL. In a preferredembodiment, the unit dose form provides a patient with an average serumlevel of iboga alkaloid of less than about 50 ng/mL.

In one embodiment, the unit dose of iboga alkaloid is from about 0.001mg to about 50 mg per day. In a preferred embodiment, the unit dose ofiboga alkaloid is from about 0.001 mg to about 30 mg per day. In anotherembodiment, the unit dose of iboga alkaloid is from about 0.001 mg toabout 20 mg per day. In another embodiment, the unit dose of ibogaalkaloid is from about 0.001 mg to about 10 mg per day. In anotherembodiment, the unit dose of iboga alkaloid is from about 0.001 mg toabout 5 mg per day. In another embodiment, the unit dose of ibogaalkaloid is from about 0.001 mg to about 1 mg per day. In anotherembodiment, the unit dose of iboga alkaloid is from about 0.001 mg toabout 0.1 mg per day. In another embodiment, the unit dose of ibogaalkaloid is from about 0.001 mg to about 0.01 mg per day. The rangesinclude both extremes as well as any subranges there between.

In another embodiment, the unit dose of iboga alkaloid is from about0.01 mg to about 50 mg per day. In another embodiment, the unit dose ofiboga alkaloid is from about 0.01 mg to about 30 mg per day. In anotherembodiment, the unit dose of iboga alkaloid is from about 0.01 mg toabout 20 mg per day. In another embodiment, the unit dose of ibogaalkaloid is from about 0.01 mg to about 10 mg per day. In anotherembodiment, the unit dose of iboga alkaloid is from about 0.01 mg toabout 5 mg per day. In another embodiment, the unit dose of ibogaalkaloid is from about 0.01 mg to about 1 mg per day. In anotherembodiment, the unit dose of iboga alkaloid is from about 0.01 mg toabout 0.1 mg per day. The ranges include both extremes as well as anysubranges there between. The ranges include both extremes as well as anysubranges there between.

In another embodiment, the unit dose of iboga alkaloid is from about 0.1mg to about 50 mg per day. In another embodiment, the unit dose of ibogaalkaloid is from about 0.1 mg to about 30 mg per day. In anotherembodiment, the unit dose of iboga alkaloid is from about 0.1 mg toabout 20 mg per day. In another embodiment, the unit dose of ibogaalkaloid is from about 0.1 mg to about 10 mg per day. In anotherembodiment, the unit dose of iboga alkaloid is from about 0.1 mg toabout 5 mg per day. In another embodiment, the unit dose of ibogaalkaloid is from about 0.1 mg to about 1 mg per day.

The ranges include both extremes as well as any subranges there between.The ranges include both extremes as well as any subranges there between.

In another embodiment, the unit dose of iboga alkaloid is from about 1mg to about 50 mg per day. In another embodiment, the unit dose of ibogaalkaloid is from about 1 mg to about 30 mg per day. In anotherembodiment, the unit dose of iboga alkaloid is from about 1 mg to about20 mg per day. In another embodiment, the unit dose of iboga alkaloid isfrom about 1 mg to about 10 mg per day. In another embodiment, the unitdose of iboga alkaloid is from about 1 mg to about 5 mg per day. Theranges include both extremes as well as any subranges there between. Theranges include both extremes as well as any subranges there between.

In one embodiment, the unit dose of iboga alkaloid is from about 5 mg toabout 50 mg per day. In a preferred embodiment, the unit dose of ibogaalkaloid is from about 5 mg to about 30 mg per day. In anotherembodiment, the unit dose of iboga alkaloid is from about 5 mg to about20 mg per day. In another embodiment, the unit dose of iboga alkaloid isfrom about 10 mg to about 50 mg per day. In another embodiment, the unitdose of iboga alkaloid is from about 10 mg to about 30 mg per day. Inanother embodiment, unit dose of iboga alkaloid is from about 10 mg toabout 20 mg per day. The ranges include both extremes as well as anysubranges there between.

In one embodiment, the unit dose of iboga alkaloid is about 0.001 mg perday. In one embodiment, the unit dose of iboga alkaloid is about 0.01 mgper day. In one embodiment, the unit dose of iboga alkaloid is about 0.1mg per day. In one embodiment, the unit dose of iboga alkaloid is about1 mg per day. In some embodiments, the unit dose of iboga alkaloid orpharmaceutically acceptable salt or solvate thereof is from about 5 mgto about 80 mg. In one embodiment, the unit dose of iboga alkaloid orpharmaceutically acceptable salt or solvate thereof is from about 10 mgto about 80 mg. In one embodiment, the unit dose of iboga alkaloid orpharmaceutically acceptable salt or solvate thereof is from about 20 mgto about 80 mg. In one embodiment, the unit dose of iboga alkaloid orpharmaceutically acceptable salt or solvate thereof is from about 30 mgto about 80 mg. In one embodiment, the unit dose of iboga alkaloid orpharmaceutically acceptable salt or solvate thereof is from about 40 mgto about 80 mg. In one embodiment, the unit dose of iboga alkaloid orpharmaceutically acceptable salt or solvate thereof is from about 50 mgto about 80 mg. In one embodiment, the unit dose of iboga alkaloid orpharmaceutically acceptable salt or solvate thereof is from about 60 mgto about 80 mg. In one embodiment, the unit dose of iboga alkaloid orpharmaceutically acceptable salt or solvate thereof is from about 70 mgto about 80 mg.

In some embodiments, the unit dose of iboga alkaloid or pharmaceuticallyacceptable salt or solvate thereof is from about 5 mg to about 50 mg. Inone embodiment, the unit dose of iboga alkaloid or pharmaceuticallyacceptable salt or solvate thereof is from about 10 mg to about 50 mg.In one embodiment, the unit dose of iboga alkaloid or pharmaceuticallyacceptable salt or solvate thereof is from about 20 mg to about 50 mg.In one embodiment, the unit dose of iboga alkaloid or pharmaceuticallyacceptable salt or solvate thereof is from about 30 mg to about 50 mg.In one embodiment, the unit dose of iboga alkaloid or pharmaceuticallyacceptable salt or solvate thereof is from about 40 mg to about 50 mg.In one embodiment, the unit dose of iboga alkaloid or pharmaceuticallyacceptable salt or solvate thereof is from about 10 mg to about 40 mg.In one embodiment, the unit dose of iboga alkaloid or pharmaceuticallyacceptable salt or solvate thereof is from about 10 mg to about 30 mg.In one embodiment, the unit dose of iboga alkaloid or pharmaceuticallyacceptable salt or solvate thereof is from about 10 mg to about 20 mg.

In one embodiment, the unit dose is about 5 mg. In one embodiment, theunit dose is about 10 mg. In one embodiment, the unit dose is about 12.5mg. In one embodiment, the unit dose is about 15 mg. In one embodiment,the unit dose is about 20 mg. In one embodiment, the unit dose is about25 mg. In one embodiment, the unit dose is about 30 mg. In oneembodiment, the unit dose is about 35 mg. In one embodiment, the unitdose is about 40 mg. In one embodiment, the unit dose is about 45 mg. Inone embodiment, the unit dose is about 50 mg. In one embodiment, theunit dose is about 60 mg. In one embodiment, the unit dose is about 70mg. In one embodiment, the unit dose is about 80 mg.

In some embodiments, the unit dose form comprises one or multipledosages of iboga alkaloid and/or opioid analgesic to be administeredperiodically, such as once, twice, three time, four times or five timedaily with iboga alkaloid or pharmaceutically acceptable salt and/orsolvate thereof. In some embodiments, the administration is once daily,or once every second day, once every third day, three times a week,twice a week, or once a week. The dosage and frequency of theadministration of the iboga alkaloid and/or opioid analgesic depends oncriteria including the route of administration, content of composition,age and body weight of the patient, condition of the patient, sex of thepatient, without limitation, as well as by the opioid analgesicemployed. Determination of the unit dose form providing a dosage andfrequency suitable for a given patient can readily be made by aqualified clinician.

These dose ranges may be achieved by transdermal, oral, or parenteraladministration of iboga alkaloid or a pharmaceutically acceptable saltand/or solvate thereof in unit dose form. Such unit dose form mayconveniently be provided in transdermal patch, tablet, caplet, liquid orcapsule form. In certain embodiments, the iboga alkaloid is provided asiboga alkaloid HCl, with dosages reported as the amount of free baseiboga alkaloid. In some embodiments, iboga alkaloid is provided insaline for intravenous administration.

Formulations

This invention further relates to pharmaceutically acceptableformulations comprising a unit dose of iboga alkaloid orpharmaceutically acceptable salt and/or solvate thereof, and optionallyan opioid analgesic, wherein the unit dose of iboga alkaloid is anamount to potentiate the opioid while maintaining an acceptable QTinterval prolongation.

In one embodiment, the pharmaceutical formulation comprises (a) at leastone opioid analgesic, (b) an effective amount of iboga alkaloid orpharmaceutically acceptable salt and/or solvate thereof to potentiatethe analgesic effect of the opioid, and (c) optionally apharmaceutically acceptable carrier. The effective amount of ibogaalkaloid is such to potentiate the opioid while maintaining anacceptable QT interval prolongation

In one embodiment, the pharmaceutical formulation comprises an opioidand an amount of iboga alkaloid so as to render the amount of opioidsufficient to provide analgesia (pain relief) to a patient whenadministered thereto. In one embodiment, the amount of iboga alkaloid issufficient to increase the analgesic effect of the amount of opioid in apatient when administered thereto.

In one embodiment, the pharmaceutical formulation comprises an opioidand an effective amount of iboga alkaloid so as to reduce tolerance orthe onset of tolerance to the opioid in a patient when administeredthereto. In one embodiment, the pharmaceutical formulation comprises anopioid and an effective amount of iboga alkaloid so as to reducedependence or the onset of dependence on the opioid in a patient whenadministered thereto.

In some embodiments, the pharmaceutical formulation comprises ibogaalkaloid and opioid analgesic at a ratio between about 100:1 and about1:100. In one embodiment, the iboga alkaloid to opioid ratio is betweenabout 100:1 and about 1:90. In one embodiment, the iboga alkaloid toopioid ratio is between about 100:1 and about 1:80. In one embodiment,the iboga alkaloid to opioid ratio is between about 100:1 and about1:70. In one embodiment, the iboga alkaloid to opioid ratio is betweenabout 100:1 and about 1:60. In one embodiment, the iboga alkaloid toopioid ratio is between about 100:1 and about 1:50. In one embodiment,the iboga alkaloid to opioid ratio is between about 100:1 and about1:40. In one embodiment, the iboga alkaloid to opioid ratio is betweenabout 100:1 and about 1:30. In one embodiment, the iboga alkaloid toopioid ratio is between about 100:1 and about 1:10. In one embodiment,the iboga alkaloid to opioid ratio is between about 100:1 and about 1:1.In one embodiment, the iboga alkaloid to opioid ratio is between about10:1 and about 1:100. In one embodiment, the iboga alkaloid to opioidratio is between about 10:1 and about 1:90. In one embodiment, the ibogaalkaloid to opioid ratio is between about 10:1 and about 1:80. In oneembodiment, the iboga alkaloid to opioid ratio is between about 10:1 andabout 1:70. In one embodiment, the iboga alkaloid to opioid ratio isbetween about 10:1 and about 1:60. In one embodiment, the iboga alkaloidto opioid ratio is between about 10:1 and about 1:50. In one embodiment,the iboga alkaloid to opioid ratio is between about 10:1 and about 1:40.In one embodiment, the iboga alkaloid to opioid ratio is between about10:1 and about 1:30. In one embodiment, the iboga alkaloid to opioidratio is between about 10:1 and about 1:20. In a preferred embodiment,the iboga alkaloid to opioid ratio is between about 10:1 and about 1:10.In one embodiment, the iboga alkaloid to opioid ratio is between about10:1 and about 1:1. The ranges include extremes as well as anysubranges.

The pharmaceutical formulation may include opioid analgesic at anyamount. For example, in some embodiments, the pharmaceutical formulationcomprises about 1 mg to about 250 mg opioid analgesic. Preferably, thepharmaceutical formulation comprises about 5 mg to about 250 mg opioidanalgesic. As would be understood by one skilled in the art, the amountof opioid analgesic in the pharmaceutical formulation is dependent onthe type of opioid analgesic, as well as other considerations (e.g.,weight of patient, age, tolerance to or dependence on an opioid, degreeof pain, and the like).

In one embodiment, the pharmaceutical formulation comprises ibogaalkaloid at from about 0.001 mg to about 50 mg. In a preferredembodiment, the pharmaceutical formulation comprises iboga alkaloid atfrom about 0.001 mg to about 30 mg. In another embodiment, thepharmaceutical formulation comprises iboga alkaloid at from about 0.001mg to about 20 mg. In another embodiment, the pharmaceutical formulationcomprises iboga alkaloid at from about 0.001 mg to about 10 mg. Inanother embodiment, the pharmaceutical formulation comprises ibogaalkaloid at from about 0.001 mg to about 5 mg. In another embodiment,the pharmaceutical formulation comprises iboga alkaloid at from about0.001 mg to about 1 mg. In another embodiment, the pharmaceuticalformulation comprises iboga alkaloid at from about 0.001 mg to about 0.1mg. In another embodiment, the pharmaceutical formulation comprisesiboga alkaloid at from about 0.001 mg to about 0.01 mg. The rangesinclude both extremes as well as any subranges there between.

In another embodiment, the pharmaceutical formulation comprises ibogaalkaloid at from about 0.01 mg to about 50 mg. In another embodiment,the pharmaceutical formulation comprises iboga alkaloid at from about0.01 mg to about 30 mg. In another embodiment, the pharmaceuticalformulation comprises iboga alkaloid at from about 0.01 mg to about 20mg. In another embodiment, the pharmaceutical formulation comprisesiboga alkaloid at from about 0.01 mg to about 10 mg. In anotherembodiment, the pharmaceutical formulation comprises iboga alkaloid atfrom about 0.01 mg to about 5 mg. In another embodiment, thepharmaceutical formulation comprises iboga alkaloid at from about 0.01mg to about 1 mg. In another embodiment, the pharmaceutical formulationcomprises iboga alkaloid at from about 0.01 mg to about 0.1 mg. Theranges include both extremes as well as any subranges there between. Theranges include both extremes as well as any subranges there between.

In another embodiment, the pharmaceutical formulation comprises ibogaalkaloid at from about 0.1 mg to about 50 mg. In another embodiment, thepharmaceutical formulation comprises iboga alkaloid at from about 0.1 mgto about 30 mg. In another embodiment, the pharmaceutical formulationcomprises iboga alkaloid at from about 0.1 mg to about 20 mg. In anotherembodiment, the pharmaceutical formulation comprises iboga alkaloid atfrom about 0.1 mg to about 10 mg. In another embodiment, thepharmaceutical formulation comprises iboga alkaloid at from about 0.1 mgto about 5 mg. In another embodiment, the pharmaceutical formulationcomprises iboga alkaloid at from about 0.1 mg to about 1 mg. The rangesinclude both extremes as well as any subranges there between. The rangesinclude both extremes as well as any subranges there between.

In another embodiment, the pharmaceutical formulation comprises ibogaalkaloid at from about 1 mg to about 50 mg. In another embodiment, thepharmaceutical formulation comprises iboga alkaloid at from about 1 mgto about 30 mg. In another embodiment, the pharmaceutical formulationcomprises iboga alkaloid at from about 1 mg to about 20 mg. In anotherembodiment, the pharmaceutical formulation comprises iboga alkaloid atfrom about 1 mg to about 10 mg. In another embodiment, thepharmaceutical formulation comprises iboga alkaloid at from about 1 mgto about 5 mg. The ranges include both extremes as well as any subrangesthere between. The ranges include both extremes as well as any subrangesthere between.

In one embodiment, the pharmaceutical formulation comprises ibogaalkaloid from about 5 mg to about 50 mg. In one embodiment, thepharmaceutical formulation comprises iboga alkaloid from about 5 mg toabout 30 mg. In another embodiment, the pharmaceutical formulationcomprises iboga alkaloid from about 5 mg to about 20 mg. In anotherembodiment, the pharmaceutical formulation comprises iboga alkaloid fromabout 10 mg to about 50 mg. In another embodiment, the pharmaceuticalformulation comprises iboga alkaloid from about 10 mg to about 30 mg. Inanother embodiment, the pharmaceutical formulation comprises ibogaalkaloid from about 10 mg to about 20 mg. The ranges include bothextremes as well as any subranges there between.

In some embodiments, the unit dose of iboga alkaloid, with or withoutopioid analgesic, is administered in one or more dosings.

In some embodiments, the formulation is designed for periodicadministration, such as once, twice, three time, four times or five timedaily with iboga alkaloid or a pharmaceutically acceptable salt and/orsolvate thereof, with or without an opioid analgesic. In someembodiments, the administration is once daily, or once every second day,once every third day, three times a week, twice a week, or once a week.The dosage and frequency of the administration depends on the route ofadministration, content of composition, age and body weight of thepatient, condition of the patient, opioid analgesic(s) administered,without limitation. Determination of dosage and frequency suitable forthe present technology can be readily made a qualified clinician.

In some embodiments, the formulation designed for administration inaccordance with the methods provide herein can be suitable for a varietyof delivery modes including, without limitation, oral and transdermaldelivery. Formulations suitable for internal, pulmonary, rectal, nasal,vaginal, lingual, intravenous, intra-arterial, intramuscular,intraperitoneal, intracutaneous and subcutaneous routes may also beused. Possible formulations include tablets, capsules, pills, powders,aerosols, suppositories, parenterals, and oral liquids, includingsuspensions, solutions and emulsions. Sustained release dosage forms mayalso be used. All formulations may be prepared using methods that arestandard in the art (see e.g., Remington's Pharmaceutical Sciences, 16thed., A. Oslo editor, Easton Pa. 1980). In a preferred embodiment, theformulation is designed for oral administration, which may convenientlybe provided in tablet, caplet, sublingual, liquid or capsule form.

EMBODIMENTS

The following embodiments are examples of methods and compositions asdescribed herein. These embodiments are by way of example only, and arenot intended to be limiting.

1. A method for potentiating the analgesic effect of an opioid analgesicin a patient undergoing or scheduled to undergo opioid analgesictherapy, the method comprising administering a potentiating amount of aniboga alkaloid or pharmaceutically acceptable salt and/or solvatethereof while maintaining a QT interval prolongation of less than about60 milliseconds (ms) during said treatment, thereby potentiating theeffect of the opioid.2. The method of embodiment 1, wherein the potentiating amount of ibogaalkaloid or pharmaceutically acceptable salt and/or solvate thereof isbetween about 5 mg and about 50 mg.3. The method of embodiment 1 or 2, wherein a QT interval prolongationof less than about 30 ms is maintained during said treatment.4. The method of any one of embodiments 1-3, further comprisingadministering iboga alkaloid or pharmaceutically acceptable salt and/orsolvate thereof concurrently with the opioid.5. The method of any one of embodiments 1-4, wherein the iboga alkaloidor pharmaceutically acceptable salt and/or solvate thereof isadministered in a formulation that further comprises the opioid.6. A method for preventing or reducing tolerance to an opioid analgesicin a patient undergoing or scheduled to undergo opioid analgesictherapy, the method comprising administering an effective amount of aniboga alkaloid or pharmaceutically acceptable salt and/or solvatethereof to prevent or reduce tolerance to the opioid while maintaining aQT interval prolongation of less than about 60 milliseconds (ms) duringsaid treatment, thereby preventing or reducing tolerance to the opioid.7. The method of embodiment 6, wherein the effective amount of ibogaalkaloid or pharmaceutically acceptable salt and/or solvate thereof isbetween about 5 mg and about 50 mg.8. The method of embodiment 6 or 7, wherein a QT interval prolongationof less than about 30 ms is maintained during said treatment.9. The method of any one of embodiments 6-8, further comprisingadministering iboga alkaloid or pharmaceutically acceptable salt and/orsolvate thereof concurrently with the opioid.10. The method of any one of embodiments 6-9, wherein the iboga alkaloidor pharmaceutically acceptable salt and/or solvate thereof isadministered in a formulation that further comprises the opioidanalgesic.11. The method of embodiment 9, wherein during concurrentadministration, the dose of opioid analgesic is reduced by about 25% toabout 75%, relative to the customary dose without iboga alkaloidadministration.12. A method for preventing dependence on an opioid analgesic in apatient undergoing or scheduled to undergo opioid analgesic therapy, themethod comprising administering an effective amount of an iboga alkaloidor pharmaceutically acceptable salt and/or solvate thereof to preventdependence on the opioid while maintaining a QT interval prolongation ofless than about 60 milliseconds (ms) during said treatment, therebypreventing dependence on the opioid.13. The method of embodiment 12, wherein the time to dependence on theopioid analgesic is increased.14. The method of embodiment 12, wherein the dose of opioid analgesic atwhich dependence occurs is increased.15. A method for preventing addiction to an opioid analgesic in apatient undergoing or scheduled to undergo opioid analgesic therapy, themethod comprising administering an effective amount of an iboga alkaloidor pharmaceutically acceptable salt and/or solvate thereof to preventaddiction to the opioid while maintaining a QT interval prolongation ofless than about 60 milliseconds (ms) during said treatment, therebypreventing addiction to the opioid.16. The method of embodiment 15, wherein the time to addiction to theopioid analgesic is increased.17. The method of embodiment 15, wherein the dose of opioid analgesic atwhich addiction occurs is increased.18. The method of any one of embodiments 12-17, wherein the effectiveamount of iboga alkaloid or pharmaceutically acceptable salt and/orsolvate thereof is between about 5 mg and about 50 mg.19. The method of any one of embodiments 12-18, wherein a QT intervalprolongation of less than about 30 ms is maintained during saidtreatment.20. The method of any one of embodiments 12-19, further comprisingadministering iboga alkaloid or pharmaceutically acceptable salt and/orsolvate thereof concurrently with the opioid.21. The method of any one of embodiments 12-20, wherein the ibogaalkaloid or pharmaceutically acceptable salt and/or solvate thereof isadministered in a formulation that further comprises the opioidanalgesic.22. The method of embodiment 21, wherein during concurrentadministration, the dose of opioid analgesic is reduced by about 25% toabout 75%, relative to the customary dose without iboga alkaloidadministration.23. The method of any one of embodiments 1-22, wherein the ibogaalkaloid is noribogaine, noribogaine derivative, or pharmaceuticallyacceptable salt and/or solvate thereof.24. The method of any one of embodiments 1-22, wherein the ibogaalkaloid is ibogaine, ibogaine derivative, or pharmaceuticallyacceptable salt and/or solvate thereof.25. The method of any one of embodiments 1-24, wherein the opioidanalgesic is selected from the group consisting of fentanyl,hydrocodone, hydromorphone, morphine, oxycodone, buprenorphine, codeine,thebaine, buprenorphine, methadone, meperidine, tramadol, tapentadol,levorphanol, sufentanil, pentazocine, and oxymorphone.26. The method of embodiment 25, wherein the opioid analgesic ismorphine.27. The method of any one of embodiments 1-26, wherein the amount ofiboga alkaloid administered to the patient is increased by about 5 mg toabout 20 mg, between six and fourteen days after iboga alkaloidadministration commences.28. A pharmaceutical formulation comprising (a) at least one opioidanalgesic, (b) an effective amount of iboga alkaloid or pharmaceuticallyacceptable salt and/or solvate thereof to potentiate the effect of theopioid as an analgesic, and (c) optionally a pharmaceutically acceptablecarrier.29. The pharmaceutical formulation of embodiment 28, wherein theeffective amount of iboga alkaloid or pharmaceutically acceptable saltand/or solvate thereof is between about 5 mg and about 50 mg.30. The pharmaceutical formulation of embodiment 28 or 29, wherein theopioid analgesic is selected from the group consisting of fentanyl,hydrocodone, hydromorphone, morphine, oxycodone, buprenorphine, codeine,thebaine, buprenorphine, methadone, meperidine, tramadol, tapentadol,levorphanol, sufentanil, pentazocine, and oxymorphone.31. The pharmaceutical formulation of embodiment 30, wherein the opioidanalgesic is morphine.32. The pharmaceutical formulation of any one of embodiments 28-31,wherein the iboga alkaloid is noribogaine, noribogaine derivative, orpharmaceutically acceptable salt and/or solvate thereof.33. The pharmaceutical formulation of any one of embodiments 28-31,wherein the iboga alkaloid is ibogaine, ibogaine derivative, orpharmaceutically acceptable salt and/or solvate thereof.34. The method of any one of embodiments 1-27 or the pharmaceuticalformulation of any one of embodiments 28-33, wherein the noribogainederivative is represented by Formula I:

or a pharmaceutically acceptable salt thereof,wherein R is hydrogen or a hydrolyzable group of the formula:

wherein X is an unsubstituted C₁-C₁₂ group or a C₁-C₁₂ group substitutedby lower alkyl or lower alkoxy groups, wherein the noribogaine havingthe hydrolyzable group hydrolyzes in vivo to form 12-hydroxy ibogamine.35. The method of any one of embodiments 1-27 or the pharmaceuticalformulation of any one of embodiments 28-33, wherein the noribogainederivative is represented by Formula II:

or a pharmaceutically acceptable salt thereof,wherein

-   -   is a single or double bond;    -   R¹ is halo, OR², or C₁-C₁₂ alkyl optionally substituted with 1        to 5 R¹⁰;    -   R² is hydrogen or a hydrolysable group selected from the group        consisting of —C(O) R^(x), —C(O)OR^(x) and —C(O)N(R^(y))₂ where        each R^(x) is selected from the group consisting of C₁-C₆ alkyl        optionally substituted with 1 to 5 R¹⁰, and each R^(y) is        independently selected from the group consisting of hydrogen,        C₁-C₆ alkyl optionally substituted with 1 to 5 R¹⁰, C₆-C₁₄ aryl        optionally substituted with 1 to 5 R¹⁰, C₃-C₁₀ cycloalkyl        optionally substituted with 1 to 5 R¹⁰, heteroaryl having 1 to 4        heteroatoms and which is optionally substituted with 1 to 5 R¹⁰,        C₁-C₁₀ heterocyclic having 1 to 4 heteroatoms and which is        optionally substituted with 1 to 5 R¹⁰, and where each R^(y),        together with the nitrogen atom bound thereto form a C₁-C₆        heterocyclic having 1 to 4 heteroatoms and which is optionally        substituted with 1 to 5 R¹⁰ or a C₁-C₆ heteroaryl having 1 to 4        heteroatoms and which is optionally substituted with 1 to 5 R¹⁰;        -   R³ is selected from the group consisting of hydrogen, C₁-C₁₂            alkyl optionally substituted with 1 to 5 R¹⁰, aryl            optionally substituted with 1 to 5 R¹⁰, —C(O)R⁶, —C(O)NR⁶R⁶            and —C(O)OR⁶;    -   R⁴ is selected from the group consisting of hydrogen,        —(CH₂)_(m)OR⁸, —CR⁷(OH)R⁸, —(CH₂)_(m)CN, —(CH₂)_(m)COR⁸,        —(CH₂)_(m)CO₂R⁸, —(CH₂)_(m)C(O)NR⁷R⁸, —(CH₂)_(m)C(O)NR⁷NR⁸R⁸,        —(CH₂)_(m)C(O)NR⁷NR⁸C(O)R⁹, and —(CH₂)_(m)NR⁷R⁸; m is 0, 1, or        2;    -   L is a bond or C₁-C₁₂ alkylene;    -   R⁵ is selected from the group consisting of hydrogen, C₁-C₁₂        alkyl substituted with 1 to 5 R¹⁰, C₁-C₁₂ alkenyl substituted        with 1 to 5 R¹⁰, —X¹—R⁷, —(X¹—Y)_(n)—X¹—R⁷, —SO₂NR⁷R⁸,        —O—C(O)R⁹, —C(O)OR⁸, —C(O)NR⁷R⁸, —NR⁷R⁸, —NHC(O)R⁹, and        —NR⁷C(O)R⁹;    -   each R⁶ is independently selected from the group consisting of        hydrogen, C₁-C₁₂ alkyl, C₂-C₁₂ alkenyl, C₂-C₁₂ alkynyl, C₆-C₁₀        aryl, C₁-C₆ heteroaryl having 1 to 4 heteroatoms, and C₁-C₆        heterocycle having 1 to 4 heteroatoms, and wherein the alkyl,        alkenyl, alkynyl, aryl, heteroaryl, and heterocycle are        optionally substituted with 1 to 5 R¹⁰;    -   X¹ is selected from the group consisting of O and S;    -   Y is C₁-C₄ alkylene or C₆-C₁₀ arylene, or a combination thereof;    -   n is 1, 2, or 3;    -   R⁷ and R⁸ are each independently selected from the group        consisting of hydrogen,

C₁-C₁₂ alkyl optionally substituted with 1 to 5 R¹⁰, C₁-C₆ heterocyclehaving 1 to 4 heteroatoms and which is optionally substituted with 1 to5R¹⁰, C₃-C₁₀ cycloalkyl optionally substituted with 1 to 5 R¹⁰, C₆-C₁₀aryl optionally substituted with 1 to 5 R¹⁰ and C₁-C₆ heteroaryl having1 to 4 heteroatoms optionally substituted with 1 to 5 R¹⁰;

-   -   R⁹ is selected from the group consisting of C₁-C₁₂ alkyl        optionally substituted with 1 to 5 R¹⁰, C₁-C₆ heterocycle having        1 to 4 heteroatoms optionally substituted with 1 to 5 R¹⁰,        C₃-C₁₀ cycloalkyl optionally substituted with 1 to 5 R¹⁰, C₆-C₁₀        aryl optionally substituted with 1 to 5 R¹⁰ and C₁-C₆ heteroaryl        having 1 to 4 heteroatoms optionally substituted with 1 to 5        R¹⁰;    -   R¹⁰ is selected from the group consisting of C₁-C₄ alkyl,        phenyl, halo, —OR¹¹, —CN, —COR¹¹, —CO₂R¹¹, —C(O)NHR¹¹, —NR¹¹R¹¹,        —C(O)NR¹¹R¹¹, —C(O)NHNHR¹¹, —C(O)NR¹¹NHR¹¹, —C(O)NR¹¹NR¹¹R¹¹,        —C(O)NHNR¹¹C(O)R¹¹, —C(O)NHNHC(O)R¹¹, —SO₂NR¹¹R¹¹,        —C(O)NR¹¹NR¹¹C(O)R¹¹, and —C(O)NR¹¹NHC(O)R¹¹; and    -   R¹¹ is independently hydrogen or C₁-C₁₂ alkyl;    -   provided that:    -   when L is a bond, then R⁵ is not hydrogen;    -   when        is a double bond, R¹ is an ester hydrolyzable group, R³ and R⁴        are both hydrogen, then -L-R⁵ is not ethyl;    -   when        is a double bond, R¹ is —OH, halo or C₁-C₁₂ alkyl optionally        substituted with 1 to 5 R¹⁰, then R⁴ is hydrogen; and    -   when is        a double bond, R¹ is OR², R⁴ is hydrogen, -L-R⁵ is ethyl, then        R² is not a hydrolyzable group selected from the group        consisting of an ester, amide, carbonate and carbamate.        36. The method of any one of embodiments 1-27 or the        pharmaceutical formulation of any one of embodiments 28-33,        wherein the noribogaine derivative is represented by Formula        III:

or a pharmaceutically acceptable salt thereof,wherein

-   -   is a single or double bond;    -   R¹² is halo, —OH, —SH, —NH₂, —S(O)₂N(R¹⁷)₂, —R^(z)-L¹-R¹⁸,        —R^(z)-L¹-R²⁰ or —R^(z)-L¹-CHR¹⁸R¹⁹, where R^(z) is O, S or        NR¹⁷;    -   L¹ is alkylene, arylene, —C(O)-alkylene, —C(O)-arylene,        —C(O)O-arylene, —C(O)O-alkylene, —C(O)NR²⁰-alkylene,        —C(O)NR²⁰-arylene, —C(NR²⁰)NR²⁰-alkylene or        —C(NR²⁰)NR²⁰-arylene, wherein L¹ is configured such that        —O-L¹-R¹⁸ is —OC(O)-alkylene-R¹⁸, —OC(O)O-arylene-R¹⁸,        —OC(O)O-alkylene-R¹⁸, —OC(O)-arylene-R¹⁸,        —OC(O)NR²⁰-alkylene-R¹⁸, —OC(O)NR²⁰-arylene-R¹⁸,        —OC(NR²⁰)NR²⁰-alkylene-R¹⁸ or —OC(NR²⁰)NR²⁰-arylene-R¹⁸, and        wherein the alkylene and arylene are optionally substituted with        1 to 2 R¹⁶;    -   R^(—)is hydrogen, —S(O)₂OR²⁰, —S(O)₂R²⁰, —C(O)R¹⁵, —C(O)NR¹⁵R¹⁵,        —C(O)OR¹⁵, C₁-C₁₂ alkyl optionally substituted with 1 to 5 R¹⁶,        C₁-C₁₂ alkenyl optionally substituted with 1 to 5 R¹⁶, or aryl        optionally substituted with 1 to 5 R¹⁶;    -   R¹⁴ is hydrogen, halo, —OR¹⁷, —CN, C₁-C₁₂ alkyl, C₁-C₁₂ alkoxy,        aryl or aryloxy, where the alkyl, alkoxy, aryl, and aryloxy are        optionally substituted with 1 to 5 R¹⁶;    -   each R¹⁵ is independently selected from the group consisting of        hydrogen, C₁-C₁₂ alkyl, C₂-C₁₂ alkenyl, C₂-C₁₂ alkynyl, aryl,        heteroaryl, and heterocycle, and wherein the alkyl, alkenyl,        alkynyl, aryl, heteroaryl, and heterocycle are optionally        substituted with 1 to 5 R¹⁶;    -   R¹⁶ is selected from the group consisting of phenyl, halo, —OR′,        —CN, —COR¹⁷, —CO₂R¹⁷, —NR¹⁷R¹⁷, —NR¹⁷C(O)R¹⁷, —NR¹⁷SO₂R¹⁷,        —C(O)NR¹⁷R¹⁷, —C(O)NR¹⁷NR¹⁷R¹⁷, —SO₂NR¹⁷R¹⁷ and        —C(O)NR¹⁷NR¹⁷C(O)R¹⁷;    -   each R¹⁷ is independently hydrogen or C₁-C₁₂ alkyl optionally        substituted with from 1 to 3 halo;    -   R¹⁸ is hydrogen, —C(O)R²⁰, —C(O)OR²⁰, —C(O)N(R²⁰)₂ or        —N(R²⁰)C(O)R²⁰;    -   R¹⁹ is hydrogen, —N(R²⁰)₂, —C(O)N(R²⁰)₂, —C(NR²⁰)N(R²⁰)₂,        —C(NSO₂R²⁰)N(R²⁰)₂, —NR²⁰C(O) N(R²⁰)₂, —NR²⁰C(S)N(R²⁰)₂,        —NR²⁰C(NR²⁰)N(R²⁰)₂, —NR²⁰C(NSO₂R²⁰)N(R²⁰)₂ or tetrazole; and    -   each R²⁰ is independently selected from the group consisting of        hydrogen, C₁-C₁₂ alkyl and aryl;    -   provided that:    -   when        is a double bond and R^(—)and R¹⁴ are hydrogen, then R¹² is not        hydroxy;    -   when        is a double bond, R¹⁴ is hydrogen, R¹² is —O-L¹-R¹⁸, —O-L¹-R¹⁹,        —O-L¹-R²⁰, and L¹ is alkylene, then —O-L¹-R¹⁸, —O-L¹-R¹⁹,        —O-L¹-R²⁰ are not methoxy;    -   when        is a double bond, R¹⁴ is hydrogen, R^(z) is O, L¹ is        —C(O)-alkylene, —C(O)-arylene, —C(O)O-arylene, —C(O)O-alkylene,        —C(O)NR²⁰-alkylene, or —C(O)NR²⁰-arylene, then none of R¹⁸, R¹⁹        or R²⁰ are hydrogen.        37. The method of any one of embodiments 1-27 or the        pharmaceutical formulation of any one of embodiments 28-33,        wherein the noribogaine derivative is represented by Formula IV:

-   -   or a pharmaceutically acceptable salt thereof,    -   wherein    -   R²¹ is selected from the group consisting of hydrogen, a        hydrolysable group selected from the group consisting of        —C(O)R²³, —C(O)NR²⁴R²⁵ and —C(O)OR²⁶, where R²³ is selected from        the group consisting of hydrogen, alkyl, substituted alkyl,        alkenyl, substituted alkenyl, alkynyl and substituted alkynyl,        R²⁴ and R²⁵ are independently selected from the group consisting        of hydrogen, alkyl, substituted alkyl, alkenyl, substituted        alkenyl, alkynyl, substituted alkynyl, aryl, substituted aryl,        heteroaryl, substituted heteroaryl, heterocyclic and substituted        heterocyclic, R²⁶ is selected from the group consisting of        alkyl, substituted alkyl, alkenyl, substituted alkenyl, alkynyl,        substituted alkynyl, aryl, substituted aryl, heteroaryl,        substituted heteroaryl, heterocyclic and substituted        heterocyclic, provided that R²¹ is not a saccharide or an        oligosaccharide;

L² is selected from the group consisting of a covalent bond and acleavable linker group;

R²² is selected from the group consisting of hydrogen, alkyl,substituted alkyl, alkenyl, substituted alkenyl, alkynyl, substitutedalkynyl, aryl, substituted aryl, cycloalkyl, substituted cycloalkyl,heteroaryl, substituted heteroaryl, heterocyclic, and substitutedheterocyclic, provided that R is not a saccharide or an oligosaccharide;

provided that when L² is a covalent bond and R²² is hydrogen, then R²¹is selected from the group consisting of —C(O)NR²⁴R²⁵ and —C(O)OR²⁶; and

further provided that when R²¹ is hydrogen or —C(O)R²³ and L² is acovalent bond, then R²² is not hydrogen.

38. The method of any one of embodiments 1-27 or the pharmaceuticalformulation of any one of embodiments 28-33, wherein the noribogainederivative is represented by Formula V:

or a pharmaceutically acceptable salt thereof,wherein:

-   -   refers to a single or a double bond provided that when        is a single bond, Formula V refers to the corresponding dihydro        compound;    -   R²⁷ is hydrogen or SO₂OR²⁹;    -   R²⁸ is hydrogen or SO₂OR²⁹;    -   R²⁹ is hydrogen or C₁-C₆ alkyl;    -   provided that at least one of R²⁷ and R²⁸ is not hydrogen.        39. The method of any one of embodiments 1-27 or the        pharmaceutical formulation of any one of embodiments 28-33,        wherein the noribogaine derivative is represented by Formula VI:

or a pharmaceutically acceptable salt thereof,wherein:

-   -   refers to a single or a double bond provided that when        is a single bond, Formula VI refers to the corresponding vicinal        dihydro compound;    -   R³⁰ is hydrogen, a monophosphate, a diphosphate or a        triphosphate; and    -   R³¹ is hydrogen, a monophosphate, a diphosphate or a        triphosphate;    -   provided that both R³⁰ and R³¹ are not hydrogen;        wherein one or more of the monophosphate, diphosphate and        triphosphate groups of R³⁰ and R³¹ are optionally esterified        with one or more C₁-C₆ alkyl esters.        40. The method of any one of embodiments 1-27 or the        pharmaceutical formulation of any one of embodiments 28-33,        wherein noribogaine or a pharmaceutically acceptable salt and/or        solvate thereof is administered.        41. The method of any one of embodiments 1-27 or the        pharmaceutical formulation of any one of embodiments 28-33,        wherein the ibogaine derivative is represented by Formula VIII:

or a pharmaceutically acceptable salt and/or solvate thereof,wherein

-   -   R¹⁰⁰ is hydrogen or C₁-C₃ alkoxy;    -   R¹⁰¹ is hydrogen, C₁-C₃ alkyl, C₁-C₃ alkoxy,        (CH₂)_(m)OC(O)alkyl, (CH₂)_(m)OH, (CH₂)_(m)Oalkyl,        (CH₂)_(m)O(CH₂)_(p)O(CH₂)_(q)O(CH₂)_(r)CH₃ or CH₂—Y—CH₃ where        each of m, p and q is 1, 2 or 3; and r is 0, 1 or 2, Y is O or        NH; and    -   R¹⁰² is H, (CH₂)_(n)OH, COOH, or COOR¹⁰⁴, where R¹⁰⁴ is C₁-C₆        alkyl or (CH₂CH₂O)_(n)CH₃, where n is 1, 2, or 3.        42. The method of any one of embodiments 1-27 or the        pharmaceutical formulation of any one of embodiments 28-33,        wherein the ibogaine derivative is selected from the group        consisting of coronaridine, ibogamine, voacangine,        18-methoxycoronaridine, 2-Methoxyethyl-18-methoxycoronaridinate,        and 18-Methylaminocoronaridine.        43. The method of any one of embodiments 1-27 or the        pharmaceutical formulation of any one of embodiments 28-33,        wherein the ibogaine derivative is selected from the group        consisting of 16-hydroxymethyl-18-hydroxyibogaline, 16-hydroxy        methyl-18-methoxyibogaline,        16-ethoxycarbonyl-18-hydroxyibogaline laurate, and        16-ethoxycarbonyl-18-hydroxyibogaline methoxyethoxymethyl ether.        44. The method of any one of embodiments 1-27 or the        pharmaceutical formulation of any one of embodiments 28-33,        wherein the ibogaine derivative is represented by Formula VIII:

or a pharmaceutically acceptable salt and/or solvate thereof,wherein

-   -   R¹⁰⁰ is OCH₃;    -   R¹⁰¹ is CH₂CH₃; and    -   R¹⁰²² is COOR¹⁰⁴, where R¹⁰⁴ is (CH₂CH₂O)_(n)CH₃, where n is 1.        45. The method of any one of embodiments 1-27 or the        pharmaceutical formulation of any one of embodiments 28-33,        wherein ibogaine or a pharmaceutically acceptable salt and/or        solvate thereof is administered.

EXAMPLES

The following Examples are intended to further illustrate certainembodiments of the disclosure and are not intended to limit its scope.Further examples and details are provided in the Appendix filedherewith, which is incorporated by reference in its entirety as part ofthe specification.

Example 1. Pharmacokinetics and Pharmacodynamics of Noribogaine inHumans

Thirty-six healthy, drug-free male volunteers, aged between 18-55 years,were enrolled in and completed the study. This was an ascendingsingle-dose, placebo-controlled, randomized double blind, parallel groupstudy. Mean (SD) age was 22.0 (3.3) years, mean (SD) height was 1.82(0.08) m, and mean (SD) weight was 78.0 (9.2) kg. Twenty-six subjectswere Caucasian, 3 were Asian, 1 Maori, 1 Pacific Islander, and 5 Other.The protocol for this study was approved by the Lower South RegionalEthics Committee (LRS/12/06/015), and the study was registered with theAustralian New Zealand Clinical Trial Registry (ACTRN12612000821897).All subjects provided signed informed consent prior to enrolment, andwere assessed as suitable to participate based on review of medicalhistory, physical examination, safety laboratory tests, vital signs andECG.

Within each dose level, 6 participants were randomized to receivenoribogaine and 3 to receive placebo, based on a computer-generatedrandom code. Dosing began with the lowest noribogaine dose, andsubsequent cohorts received the next highest dose after the safety,tolerability, and blinded pharmacokinetics of the completed cohort werereviewed and dose-escalation approved by an independent Data SafetyMonitoring Board. Blinded study drug was administered as a capsule with240 ml of water after an overnight fast of at least 10 hours.Participants did not receive any food until at least 5 hours post-dose.Participants were confined to the study site from 12 hours prior to drugadministration, until 72 hours post-dose, and there were subsequentoutpatient assessments until 216 hours post-dose.

Blood was obtained for pharmacokinetic assessments pre-dose and then at0.25, 0.5, 0.75, 1.0, 1.25, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 7,8, 10, 12, 14, 18, 24, 30, 36, 48, 60, 72, 96, 120, 168 and 216 hourspost-dose. Samples were centrifuged and plasma stored at −70° C. untilanalyzed. Block 24 hour urine collections were obtained following studydrug administration for the 30 and 60 mg cohorts. Aliquots were frozenat −20° C. until analyzed.

Pulse oximetry and capnography data were collected continuously using aGE Carescape B650 monitoring system from 2 hours prior to dosing anduntil six hours after dosing, and thereafter at 12, 24, 48 and 72 hourspost-dosing. Additional oximetry data were collected at 120, 168 and 216hours. Pupillary miosis was assessed by pupillometry. Dark-adapted pupildiameter was measured in triplicate using a Neuroptics PLR-200pupillometer under standardized light intensity (<5 lux) pre-dose, andat 2, 4, 6, 12, 24, 48, 72, 96, 120, 168 and 216 hours post-dosing.

Plasma noribogaine concentrations were determined in the 3 mg and 10 mgdose groups using a validated, sensitive LCMSMS method. Samplepreparation involved double extraction of basified plasma samples withtert-butyl methyl ether, drying the samples under a stream of nitrogenand reconstitution of sample with acetonitrile:B.P. water (5:95, v/v)containing 0.1% (v/v) formic acid. The compounds were separated by a150×2.0 mm Luna 5 μm C18 column and detected with a triple-quadrupoleAPI 4000 or 5000 mass spectrometer using electrospray ionization inpositive mode and multiple reaction monitoring. Noribogaine-d4 was usedas the internal standard. The precursor-product ion transition valuesfor noribogaine were m/z 297.6->122.3, and for the internal standardnoribogaine-d₄ m/z 301.1->122.2. Analyst® software was used for dataacquisition and processing. The ratio of the peak area of noribogaine tothe internal standard noribogaine-d4 was used for calibration andmeasurement of the unknown concentration of noribogaine. The lower limitof quantification (LLOQ) was 0.025 ng/ml noribogaine. The calibrationcurve was between 0.025 and 25.600 ng/ml noribogaine. Mobile phase A wasacetonitrile:B.P. water (5:95, v/v) containing 0.1% (v/v) formic acid,and mobile phase B was acetonitrile:B.P. water (95:5, v/v) containing0.1% (v/v) formic acid. Total run time was 6 minutes. Binary flow:Initial concentration was 8% mobile phase B; hold at 8% mobile phase Bfor 0.5 minutes and linear rise to 90% mobile phase B over 1.5 minutes;hold at 90% mobile phase B for 1 minute and then drop back to 8% mobilephase B over 0.01 minute. Equilibrate system for 3 minutes. Total runtime was 6 minutes. Within- and between-day assay precision was <9%, andwithin- and between-day assay accuracy was <9%.

Plasma noribogaine concentrations were determined in the 30 mg and 60 mgdose groups using a validated, sensitive LCMSMS method. Samplepreparation involved deproteinization of plasma samples withacetonitrile and dilution of sample with 0.1% (v/v) formic acid. Thecompounds were separated by a 150×2.0 mm Luna 5 μm C18 column anddetected with a triple-quadrupole API 4000 or 5000 mass spectrometerusing electrospray ionization in positive mode and multiple reactionmonitoring. Noribogaine-d4 was used as the internal standard. Theprecursor-product ion transition values for noribogaine were m/z297.6->122.3, and for the internal standard noribogaine-d4 m/z301.1->122.2. Analyst® software was used for data acquisition andprocessing. The ratio of the peak area of noribogaine to the internalstandard noribogaine-d4 was used for calibration and measurement of theunknown concentration of noribogaine. The LLOQ was 0.50 ng/mlnoribogaine. The calibration curve was between 0.50 and 256.00 ng/mlnoribogaine. Mobile phase was the same as method A, and binary flow wasalso the same as method A. The within- and between-day assay precisionwas <9%, and the within- and between-day assay accuracy was <9%.

Plasma noribogaine glucuronide concentrations were determined in the 30mg and 60 mg dose groups using a validated sensitive LCMSMS method.Sample preparation involved deproteinization of plasma samples withacetonitrile, drying the samples under a stream of nitrogen andreconstitution of sample with acetonitrile: B.P. water (5:95, v/v)containing 0.1% (v/v) formic acid. The compounds were separated by a150×2.0 mm Luna 5 μm C18 column and detected with a triple-quadrupoleAPI 4000 or 5000 mass spectrometer using electrospray ionization inpositive mode and multiple reaction monitoring. Noribogaine-d4 was usedas the internal standard. The precursor-product ion transition valuesfor noribogaine glucuronide were m/z 472.8->297.3, and for the internalstandard noribogaine-d4 m/z 301.1->122.2. Analyst® software was used fordata acquisition and processing. The ratio of the peak area ofnoribogaine glucuronide to the internal standard noribogaine-d4 was usedfor calibration and measurement of the unknown concentration ofnoribogaine glucuronide. The LLOQ was 0.050 ng/ml noribogaineglucuronide. The calibration curve was between 0.050 and 6.400 ng/mlnoribogaine glucuronide. Mobile phases was the same as method A. Binaryflow: Initial concentration was 6% mobile phase B; hold at 6% mobilephase B for 0.5 minutes and linear rise to 90% mobile phase B over 2minutes; hold at 90% mobile phase B for 1 minute and then drop back to6% mobile phase B over 0.01 minute. Equilibrate system for 3.5 minutes.Total run time was 7 minutes. The within- and between-day assayprecision was <11%, and the within- and between-day assay accuracy was<10%.

Urine noribogaine and noribogaine glucuronide concentrations weredetermined in the 30 mg and 60 mg dose groups using a validatedsensitive LCMSMS method. Sample preparation involved deproteinization ofurine samples with acetonitrile and dilution of the sample with 0.1%(v/v) formic acid. The compounds were separated by a 150×2.0 mm Luna 5μm C18 column and detected with a triple-quadrupole API 5000 massspectrometer using electrospray ionization in positive mode and multiplereaction monitoring. Noribogaine-d4 was used as the internal standard.The precursor-product ion transition values for noribogaine were m/z297.6->122.3, noribogaine glucuronide m/z 472.8->297.3, and for theinternal standard noribogaine-d4 m/z 301.1->122.2. Analyst® software wasused for data acquisition and processing. The ratios of the peak area ofnoribogaine and noribogaine glucuronide to the internal standardnoribogaine-d4 were used for calibration and measurement of the unknownconcentration of noribogaine and its glucuronide. Assay LLOQ was 20.0ng/ml for noribogaine and 2.0 ng/ml for noribogaine glucuronide. Thecalibration curve was between 20.0 and 5120.0 ng/ml noribogaine, and 2.0and 512.0 ng/ml noribogaine glucuronide. Mobile phases were as describedin method A, and binary flow as in method C. The within- and between-dayassay precision was <13%, and within- and between-day assay accuracy was<12%.

Noribogaine and noribogaine glucuronide concentrations above the limitof quantification were used to calculate pharmacokinetic parametersusing model-independent methods. The maximum plasma concentration (Cmax)and time to maximum plasma concentration (Tmax) were the observedvalues. Plasma concentration data in the post-distribution phase of theplasma concentration-time plot were fitted using linear regression tothe formula ln C=ln Co −t.Kel, where Co was the zero-time intercept ofthe extrapolated terminal phase and Kel was the terminal eliminationrate constant. The half-life (t_(1/2)) was determined using the formulat_(1/2)=0.693/Kel. The area under the concentration-time curve (AUC)from time zero to the last determined concentration-time point (tf) inthe post distribution phase was calculated using the trapezoidal rule.The area under the curve from the last concentration-time point in thepost distribution phase (Ctf) to time infinity was calculated fromAUC_(t-∞)=Ctf/Kel. The concentration used for Ctf was the lastdetermined value above the LLOQ at the time point. The total AUG_(0-∞)was obtained by adding AUC_(tf) and AUC_(t-∞). Noribogaine apparentclearance (CL/F) was determined using the formulaCL/F=Dose/AUC_(0-∞)×1000, and apparent volume of distribution (Vd/F) wasdetermined using the formula Vd/F=(CL/F)/Kel. Total urine noribogainewas the sum of both analytes.

Summary statistics (means, standard deviations, and coefficients ofvariation) were determined for each dose group for safety laboratorytest data, ECG and pharmacokinetic parameters, and pharmacodynamicvariables. Categorical variables were analysed using counts andpercentages. Dose-proportionality of AUC and Cmax was assessed usinglinear regression. The effect of dose on pharmacodynamic parametervalues over time was assessed using two-factor analysis of variance(ANOVA). Pairwise comparisons (with Tukey-Kramer adjustment) betweeneach dose group to the placebo were conducted at each time point usingthe least squares estimates obtained from the ANOVA, using SAS ProcMixed (SAS ver 6.0).

Results

Pharmacokinetics: Mean plasma concentration-time plots of noribogaineare shown in FIG. 1, and mean pharmacokinetic parameters are shown inTable 1.

TABLE 1 3 mg 10 mg 30 mg 60 mg (n = 6) (n = 6) (n = 6) (n = 6)Noribogaine (mean (SD)) (mean (SD)) (mean (SD)) (mean (SD) AUC_(0-∞)74.2 254.5 700.4 1962.2 (ng · hr/ml) (13.1) (78.9) (223.3) (726.5)AUC₀₋₂₁₆ 72.2 251.4 677.6 1935.4 (ng · hr/ml) (13.2) (78.5) (221.1)(725.4) Cmax 5.2 14.5 55.9 116.0 (ng/ml) (1.4) (2.1) (14.8) (22.5) Tmax(hr) 1.9 (0.6) 2.9 1.8 2.4 (1.8) (0.6) (0.6) t_(1/2) (hr) 40.9 49.2 27.629.1 (8.7) (11.5) (7.0) (9.3) Vd/F (L) 2485.1 3085.8 1850.8 1416.8(801.5) (1197.0) (707.9) (670.1) CL/F (L/h) 41.4 (7.0) 42.3 (12.0) 46.9(16.4) 34.0 (11.4) Noribogaine glucuronide AUC_(0-∞) — — 25.8 (9.3) 67.1(21.9) (ng · hr/ml) AUC₀₋₂₁₆ — — 25.7 (9.1) 65.0 (21.5) (ng · hr/ml)Cmax — — 1.8 (0.6) 4.1 (1.2) (ng/ml) Tmax (hr) — — 3.0 (0.6) 3.8 (1.2)t_(1/2) (hr) — — 20.6 (4.9) 23.1 (3.0)

Noribogaine was rapidly absorbed, with peak concentrations occurring 2-3hours after oral dosing. Fluctuations in individual distribution-phaseconcentration-time profiles may suggest the possibility of enterohepaticrecirculation (see highlighted individual 4-8 hour profiles in FIG. 1,insert). Both Cmax and AUC increased linearly with dose (Table 1, upperpanel). Mean half-life estimates of 28-50 hours were observed acrossdose groups for noribogaine. Volume of distribution was extensive(1417-3086 L across dose groups).

Mean plasma noribogaine glucuronide concentration-time plots for the 30mg and 60 mg dose group are shown in FIG. 2, and mean pharmacokineticparameters are shown in Table 1, lower panel. Noribogaine glucuronidewas detected in all subjects by 0.75 hours, with peak concentrationsoccurring 3-4 hours after noribogaine dosing. Mean half-life of 21-23hours was estimated for plasma noribogaine glucuronide. The proportionof noribogaine glucuronide Cmax and AUC relative to noribogaine was 3-4%for both dose groups. Total urine noribogaine elimination was 1.16 mgand 0.82 mg for the 30 mg and 60 mg dose groups respectively,representing 3.9% and 1.4% of the doses administered.

Pharmacodynamics: There was no evidence of pupillary constriction insubjects dosed with noribogaine. No between-dose group differences inpupil diameter were detected over time. After adjusting for baselinedifferences, comparison of each dose group with placebo by ANOVA showedno statistically significant differences (p>0.9).

Noribogaine treatment showed no analgesic effect in the cold pressortest. Analgesic effect was assessed based on duration of hand immersionin ice water and on visual analog scale (VAS) pain scores upon handremoval from the water bath. For duration of hand immersion, afteradjusting for baseline differences, comparison of each dose group withplacebo by ANOVA showed no statistically significant differences(p>0.9). Similarly, for VAS pain scores, after adjusting for baselinedifferences, comparison of each dose group with placebo by ANOVA showedno statistically significant differences (p=0.17).

Example 2. Safety and Tolerability of Noribogaine in Humans

Safety and tolerability of noribogaine were tested in the group ofvolunteers from Example 1. Cold pressor testing was conducted in 1° C.water according to the method of Mitchell et al. (J. Pain 5:233-237,2004) pre-dose, 6, 24, 48, 72 and 216 hours post-dosing. Safetyevaluations included clinical monitoring, recording of adverse events(AEs), safety laboratory tests, vital signs, ECG telemetry from −2 h to6 h after dosing, and 12-lead electrocardiograms (ECGs) up to 216 hourspost-dosing.

Results

A total of thirteen adverse events were reported by seven participants(Table 2). Six adverse events were reported by three participants in theplacebo group, five adverse events were reported by two subjects in the3 mg dose group, and one adverse event was reported by single subjectsin the 10 mg and 30 mg dose groups, respectively. The most commonadverse events were headache (four reports) and epistaxis (two reports).All adverse events were of mild-moderate intensity, and all resolvedprior to study completion. There were no changes in vital signs orsafety laboratory tests of note. In particular, there were no changes inoximetry or capnography, or changes in respiratory rate. There were noQTcF values >500 msec at any time. One subject dosed with 10 mgnoribogaine had a single increase in QTcF of >60 msec at 24 hourspost-dosing.

TABLE 2 Dose (mg) Mild Moderate Severe Placebo Blepharitis Epistaxis —Bruising Dry Skin Eye pain, nonspecific Infection at cannula site 3 Backpain Headache — Dizziness Epistaxis Headache 10 Headache — — 30 Headache— — 60 — — —

Example 3. Safety, Tolerability, and Efficacy of Noribogaine inOpioid-Addicted Humans

The efficacy of noribogaine in humans was evaluated in opioid-dependentparticipants in a randomized, placebo-controlled, double-blind trial.Patients had been receiving methadone treatment as the opioidsubstitution therapy, but were transferred to morphine treatment priorto noribogaine administration. This was done to avoid negativenoribogaine-methadone interactions that are not observed betweennoribogaine and methadone. See U.S. Application Publication No.2014/0288056, filed Mar. 14, 2014, and U.S. application Ser. No.14/346,655, filed Mar. 21, 2014, which are incorporated herein byreference in their entireties.

Three cohorts of nine (9) subjects (6 administered noribogaine and 3administered placebo in each cohort) were evaluated for tolerability,pharmacokinetics, and efficacy. Cohort 1 received a single dose of 60 mgnoribogaine or placebo. Cohort 2 received a single dose of 120 mgnoribogaine or placebo. Cohort 3 received a single dose of 180 mgnoribogaine or placebo. Treatment was administered 2 hours after lastmorphine dose and the time to resumption of morphine (opioidsubstitution treatment, OST) was determined. Few adverse effects ofnoribogaine were observed in any of the participants, including nohallucinatory effects. Table 3 shows the reported adverse events foreach treatment.

TABLE 3 Treatment Emergent Adverse Events Summary System Organ ClassPlacebo 60 mg 120 mg 180 mg Preferred Term (N = 9) (N = 6) (N = 6) (N =6) Number of Subjects Reporting any AEs 19:7 15:5 (83.3%) 28:6 17:4(66.7%) (77.8%) (100.0%) Ear and Labyrinth Disorders 0 0 2:2 (33.3%) 0Tinnitus 0 0 2:2 (33.3%) 0 Eye Disorders 2:2 (22.2%) 3:3 (50.0%) 5:5(83.3%) 5:4 (66.7%) Visual Impairment 2:2 (22.2%) 2:2 (33.3%) 5:5(83.3%) 5:4 (66.7%) Dry Eye 0 1:1 (16.7%) 0 0 Gastrointestinal Disorders3:2 (22.2%) 2:2 (33.3%) 7:2 (33.3%) 4:2 (33.3%) Nausea 1:1 (11.1%) 0 3:2(33.3%) 2:2 (33.3%) Dry Mouth 0 0 1:1 (16.7%) 1:1 (16.7%) Vomiting 0 02:1 (16.7%) 1:1 (16.7%) Diarrhoea 1:1 (11.1%) 0 1:1 (16.7%) 0 Dyspepsia1:1 (11.1%) 2:2 (33.3%) 0 0 General Disorders and Administration Site4:3 (33.3%) 0 2:2 (33.3%) 1:1 (16.7%) Conditions Catheter Site RelatedReaction 0 0 0 1:1 (16.7%) Catheter Site Pain 3:2 (22.2%) 0 2:2 (33.3%)0 Malaise 1:1 (11.1%) 0 0 0 Infections and Infestations 1:1 (11.1%) 01:1 (16.7%) 2:2 (33.3%) Cellulitis 0 0 1:1 (16.7%) 1:1 (16.7%) UrinaryTract Infection 0 0 0 1:1 (16.7%) Catheter Site Infection 1:1 (11.1%) 00 0 Musculoskeletal and Connective Tissue 1:1 (11.1%) 2:1 (16.7%) 0 2:2Disorders (33.3%) Back Pain 1:1(11.1%) 2:1 (16.7%) 0 1:1 (16.7%) LimbDiscomfort 0 0 0 1:1 (16.7%) Nervous System Disorders 7:5 (55.6%) 7:4(66.7%) 5:4 (66.7%) 3:2 (33.3%) Headache 6:5 (55.6%) 7:4 (66.7%) 2:2(33.3%) 3:2 (33.3%) Hyperaesthesia 0 0 1:1 (16.7%) 0 Pseudoparalysis 0 01:1 (16.7%) 0 Tremor 0 0 1:1 (16.7%) 0 Somnoience 1:1 (11.1%) 0 0 0Psychiatric Disorders 1:1 (11.1%) 1:1 (16.7%) 0 0 Depressed Mood 0 1:1(16.7%) 0 0 Euphoric Mood 1:1 (11.1%) 0 0 0 Respiratory, Thoracic andMediastinal 0 0 4:2 (33.3%) 0 Disorders Epistaxis 0 0 2:1 (16.7%) 0Orophaiyngeal Pain 0 0 1:1 (16.7%) 0 Rhinorrhoea 0 0 1:1 (16.7%) 0 Skinand Subcutaneous Tissue Disorders 0 0 2:1 (16.7%) 0 Skin Discomfort 0 01:1 (16.7%) 0 Skin Irritation 0 0 1:1 (16.7%) 0 Note: Within each systemorgan class, Preferred Terms are presented by descending incidence ofdescending dosages groups and then the placebo group. Note: N = numberof subjects in the safety population.

FIG. 3 indicates the average serum noribogaine concentration over timeafter administration of noribogaine for each cohort (60 mg, diamonds;120 mg, squares; or 180 mg, triangles).

Results

Pharmacokinetic results for each cohort are given in Table 4. Maximumserum concentration of noribogaine (Cmax) increased in a dose-dependentmanner. Time to Cmax (Tmax) was similar in all three cohorts. Meanhalf-life of serum noribogaine was similar to that observed in healthypatients.

TABLE 4 Pharmacokinetic results from the Patients in Phase IB StudyCohort 1 (60 mg) Cohort 2 (120 mg) Cohort 3 (180 mg) Data (mean ± SD)Data (mean ± SD) Data (mean ± SD) PK parameter [range] [range] [range]Cmax (ng/ml) 81.64 ± 23.77 172.79 ± 30.73 267.88 ± 46.92 [41.29-113.21][138.84-229.55] [204.85-338.21] Tmax (hours) 3.59 ± 0.92 2.99 ± 1.234.41 ± 01.80 [2.50-5.00] [0.98-4.02] [3.00-8.00] AUC_((0-T)) 2018.01 ±613.91 3226.38 ± 1544.26 6523.28 ± 2909.80 (ng · hr/m1)[1094.46-2533.44] [1559.37-5638.98] [3716.69-10353.12] AUC_((0-¥))2060.31 ± 609.39 3280.50 ± 1581.43 6887.67 ± 3488.91 (ng · hr/m1)[1122.29-2551.63] [1595.84-5768.52] [3734.21-12280.91] Half-life (hrs)29.32 ± 7.28 30.45 ± 9.14 23.94 ± 5.54 [18.26-37.33] [21.85-48.33][19.32-34.90] Vd/F 1440.7 ± 854.0 2106.43 ± 1644.54 1032.19 ± 365.30[619.5-2772.5] [824.24-5243.78] [581.18-1608.98] Cl/F 32.14 ± 12.3844.68 ± 21.40 31.47 ± 13.12 [23.51-53.46] [20.80-75.20] [14.66-48.20]

FIG. 4 indicates the time to resumption of morphine (OST) for patientstreated with placebo (circles), 60 mg noribogaine (squares), 120 mgnoribogaine (triangles), and 180 mg noribogaine (inverted triangles).Patients receiving a single 120 mg dose of noribogaine exhibited anaverage time to resumption of opioids of greater than 20 hours. Patientsreceiving a single 180 mg dose of noribogaine exhibited an average timeto resumption of opioids similar to that of placebo. This demonstratesthat increasing the dose of noribogaine to 180 mg results in a shortertime to resumption of OST than observed in patients receiving 120 mgnoribogaine. Time to resumption of OST after treatment with 180 mg wasstill longer than untreated patients (7 hours, not shown) or thoseadministered 60 mg noribogaine.

Patients were evaluated based on the Clinical Opiate Withdrawal Scale(COWS), Subjective Opiate Withdrawal Scale (SOWS), and Objective OpiateWithdrawal Scale (OOWS) scoring systems over the period of time betweenadministration of noribogaine (or placebo) until resumption of OST.These scales are outlined in Guidelines for the Psychosocially AssistedPharmacological Treatment of Opioid Dependence, World HealthOrganization, Geneva (2009), Annex 10, which is incorporated herein byreference in its entirety. The scales measure the intensity ofwithdrawal symptoms, based on clinical, subjective, and objectiveindicia.

FIG. 5 shows the COWS scores at time of resumption of OST for eachcohort. Box includes values representing 25%-75% quartiles.Diamond=median; crossbar in box=mean; whiskers=values within standarddeviation of mid-quartiles. No outliers present. The highly variableCOWS scores across and within each cohort indicates that patients wereresuming opiates without relation to the intensity of withdrawal. Thiswas also reflected in SOWS and OOWS scores at the time of resumption ofOST.

FIG. 6A shows the mean change in total COWS scores over the first sixhours following dosing and prior to resumption of OST. FIG. 6B shows themean AUC(0-6 hours) of the COWS total score change from baseline. FIG.7A shows the mean change in total OOWS scores over the first six hoursfollowing dosing and prior to resumption of OST. FIG. 7B shows the meanAUC(0-6 hours) of the OOWS total score change from baseline. FIG. 8Ashows the mean change in total SOWS scores over the first six hoursfollowing dosing and prior to resumption of OST. FIG. 8B shows the meanAUC(0-6 hours) of the SOWS total score change from baseline. These dataindicate that withdrawal symptoms get worse over time after cessation ofOST, and that patients administered placebo experience generally worsewithdrawal symptoms over that period. Patients who received 120 mgnoribogaine generally experienced fewer withdrawal symptoms than theother patients, regardless of the scale used. Patients administeredplacebo generally experienced more withdrawal symptoms than patients whowere administered noribogaine.

Patients' QT intervals were evaluated at regular time points throughoutthe study. FIG. 9A shows the average change in QT interval (ΔQTcl, i.e.,QT interval prolongation) over the first 24 hours post noribogaine (orplacebo) administration. FIG. 9B shows the relationship betweennoribogaine concentrations and ΔΔQTcI with 90% CI. There is adose-dependent increase in QT interval prolongation that is correlatedwith the serum concentration of noribogaine. A goodness-of-fit plot forthe observed and predicted relation between noribogaine plasma levelsand ΔΔQTcI is provided in FIG. 9C.

Example 4. Efficacy of Noribogaine to Potentiate Opioid Analgesic Effectin Humans Case 1

A male patient, age 35, undergoing opioid analgesic therapy for chronicback pain, is treated with noribogaine hydrochloride at the dosesindicated in Table 5, concurrently with the opioid. The amount of opioidanalgesic administered to the patient is about half of the customarydose given in a similar situation without noribogaine co-treatment. Thepatient does not exhibit tolerance to or dependence on the opioid duringthe study period. Table 5 and FIG. 10 indicate the projected serumconcentration and increase in QTcl during the course of treatment. Datais estimated based on the human trial data provided in Examples 1-3.

TABLE 5 Projected Mean Projected Plasma Mean QTcl INPUT Conc ng/mLIncrease in Dose # DOSE mg pre-dose msec pre-dose 1 10 9 3 2 10 9 3 3 108 3 4 10 8 3 5 10 7 3 6 10 5 2 7 20 7 3 8 20 8 3 9 20 8 3 10 20 9 3 1120 9 3 12 20 13 4 13 20 15 4 14 20 16 4 15 30 17 4 16 30 17 4 17 30 17 418 30 17 4 19 30 17 4 20 30 22 5 21 30 24 6 22 30 25 6

Case 2

A female patient, age 42, undergoing opioid analgesic therapy for acutepain, is treated with noribogaine hydrochloride at the doses indicatedin Table 6, concurrently with the opioid. The amount of opioid analgesicadministered to the patient is slightly above half of the customary dosegiven in a similar situation without noribogaine co-treatment. Thepatient does not exhibit tolerance to or dependence on the opioid duringthe study period. Table 6 and FIG. 11 indicate the projected serumconcentration and increase in QTcl during the course of treatment. Dataare estimated based on the human trial data provided in Examples 1-3.

TABLE 6 INPUT Projected Mean Projected Mean DOSE Plasma Conc QTclIncrease in Dose # mg ng/mL pre-dose msec pre-dose 1 20 17 4 2 20 17 4 320 17 4 4 20 15 4 5 20 13 4 6 20 9 3 7 30 13 4 8 20 15 4 9 30 17 4 10 2017 4 11 30 17 4 12 20 22 5 13 30 19 5 14 30 23 5 15 30 20 5 16 30 23 517 30 20 5 18 30 23 5 19 30 25 6

Example 5. Noribogaine is a G-Protein Biased κ-Opioid Receptor AgonistSelected Abbreviations and Acronyms

GPCR: G protein-coupled receptorOPRM: μ-opioid receptorOPRK: κ-opioid receptorOPRD: δ-opioid receptorNorBNI: nor-binaltorphimineDAMGO: [D-Ala2, NMe-Phe4, Gly-ol5]-enkephalin

5.1: Materials and Methods Materials

[Phenyl-3, 4-³H]-U-69,593 (43.6 Ci/mmol), [Tyrosyl-3, 5-³H(N)]-DAMGO([D-Ala², N-MePhe⁴, Gly⁵-ol]-enkephalin) (50 Ci/mmol) and [35S]GTPγS(Guanosine 5″-(gamma-thio)triphosphate) (1250 Ci/mmol) were purchasedfrom PerkinElmer Life Sciences (Boston, Mass.). U69,593, naloxone,nor-binaltorphimine (nor-BNI), morphine, nalmefene, dynorphin A, DAMGO,GTPγSyS, GDP and all buffer constituents were purchased fromSigma-Aldrich Corp. (St. Louis, Mo.). CHO-K1 cell lines expressing humanopioid receptors were provided by Dr. Toll at Torrey Pines Institute.Ibogaine was provided by Dr. Mash at the University of Miami (Miami,Fla.). 18-methoxycoronaridine (18-MC) was purchased at OrbiterPharmaceutical. Noribogaine hydrochloride was purchased at Sigma AldrichChemie GmbH (Buchs, Switzerland).

Membrane Preparation

Membranes from rat midbrain tissues were purchased at Chantest(Cleveland, Ohio). Membranes of human OPRK were purchased fromPerkinElmer Life Sciences (Boston, Mass.) and human OPRM CHO-K1 cellswere prepared as described below. Adherent cells were harvested on ice,with cold PBS and a cell scraper, pelleted and frozen at −80° C.overnight. Cell lysis was performed at 4° C. in 50 mM Tris (pH 7), 2.5mM EDTA and cOmplete protease inhibitor cocktail (cOmplete, F.Hoffmann-La Roche Ltd). Cells were homogenized with a polytron andcentrifuged at 2500 rpm for 10 min at 4° C. Supernatant was recoveredand the process was repeated once. Supernatant was centrifuged at 21,000rpm for 90 min at 4° C. and pellets were re-suspended in 50 mM Tris (pH7) and 0.32M sucrose. Total protein concentration was evaluated using aThermo Scientific NanoDrop spectrophotometer and by Bradford assayMembrane sample aliquots were stored at −80° C. at 1 to 5 mg/mL proteinconcentration. Membranes from brain tissues were stored in 50 mM Tris(pH 7), 1 mM EDTA and 0.32M sucrose with protease inhibitors cocktail.

Radioligand Binding

Competitive binding experiments were performed using Perkin Elmerrecommended conditions. Membranes were thawed on ice and diluted inbinding buffer 50 mM Tris-HCl pH 7.4, 5 mM MgCl₂ at 5 μg of membrane perreaction. Competition binding assay experiment were performed in 500 μLtotal volume containing [³H]U69,593 (0.88 nM) for OPRK membranes or[³H]DAMGO (0.75 nM) for OPRM membranes in the presence of increasingconcentrations of each unlabeled drug (noribogaine, ibogaine, 18-MC,U69,593, morphine, DAMGO, naloxone) for 60 minutes at 25° C. Nonspecificbinding was defined in the presence of 1 μM naloxone. Bound and freeradiolabelled ligands were separated by filtration using a MicroBetaFilterMate-96 Harvester and wash 6×1 mL with ice cold wash buffer (50 mMTris-HCl pH 7.4) over GF/B filter (presoaked in 0.5% BSA) (Perkin Elmer,Waltham, Mass.). Radioactivity counts were determined using Perkin ElmerMicro Peta microplate counter with scintillation cocktail MicroScint-20™according to manufacturer recommendations. Data were collected and thehalf maximal inhibitory concentration (IC₅₀) and apparent bindingaffinity (K_(i)) for all data sets were calculated with GraphPad Prism5.04.

[³⁵S]GTPγS Binding Assay

[³⁵S]GTPγS binding to Ga proteins was determined using a modifiedprocedure from (Toll, Berzetei-Gurske et al. 1998). Cell membranes werethawed on ice and experiments were carried out in a 96-well format. Cellmembranes (10 μg per reaction) were incubated in a binding buffer (20 mMHEPES, pH 7.4, 100 mM NaCl, 10 mM MgCl_(2X)6H₂O, 0.2% bovine serumalbumin, and GDP 10 μM, pH 7.4) containing 80 pM [³⁵S]GTPγS and varyingconcentrations of opioid agonists (U69,593, DAMGO, morphine, dynorphinA, nalmefene, or noribogaine) in a total volume of 100 μL for 60 min at25° C. Membranes were pre-incubated with the GDP for 15 min on ice priorto the addition of ligands. Antagonists were added to the membranesolution 20 min prior the addition of the agonist, and [³⁵S]GTPγS wasadded 5 min after the agonist. Non-specific and basal levels of GTPγSbinding was evaluated by using 10 μM cold GTPγS and binding buffer,respectively. Bound and free [³⁵S]GTPγS were separated by filtrationusing a MicroBeta FilterMate-96 Harvester and wash 4×1 mL with ice coldwash buffer (20 mM Tris, pH 7.4, and 2.5 mM MgCl_(2X)6H₂O, pH 7.4) overGF/B filter (presoaked in 0.5% BSA) (Perkin Elmer, Waltham, Mass.).Radioactivity counts were determined using Perkin Elmer Micro βetamicroplate counter with scintillation cocktail MicroScint-20™ accordingto manufacturer recommendations. Data were collected and the halfmaximal effective concentration (EC₅₀) and maximal responses (E_(max))values were calculated with GraphPad Prism 5.04.

β-Arrestin-2 Recruitment Assay

The PathHunter enzyme complementation Arrestin-2 Recruitment assay wasperformed at DiscoveRx Corporation, Fremont, Calif. This assay utilizedCHO-K1 cells stably transfected to overexpress β-arrestin-2 fused to aβ-galactosidase fragment together with human OPRK gene (NM_000912.3,human KOR) or human OPRM gene (NM_000914.3, encoding human MOR).Briefly, when β-arrestin-2 travels to active receptor, the complementaryβ-galactosidase fragments fused to the receptor and β-arrestin interactto form a functional enzyme with activity that is detected bychemiluminescence. For all in vitro assays, data were normalized as apercentage of control agonist responses, typically defined by dynorphinA stimulated activity in the OPRK assays, and [Met] Enkephalinstimulated activity in the OPRM assays. For agonist dose-responseexperiments, cells were treated with test compound for 90 min prior toassessment of enzyme complementation. For antagonist dose-inhibitionexperiments, the cells were incubated with the test compound for 30 minprior to agonist addition. For OPRK, a dose corresponding to the EC₅₀(316.9 nM) of Dynorphin A was used. For OPRM a dose corresponding to theEC₅₀ (2.1 μM) of [Met] Enkephalin was used.

Data Analysis

The IC₅₀ and K_(i) values for ligands in the radioactive binding assayswere determined by fitting competition binding data of individualexperiments normalized to buffer (total binding) and 1 μM naloxone(nonspecific binding) to a single site competition model in GraphPadPrism 5.04 using the transformation of Cheng and Prusoff (CFeq):K_(i)=IC₅₀/(1+[S]/K_(m)), where [S] is the concentration of agonist andK_(m) is the K_(i) value for [³H]U69,593 and [³H]DAMGO determined byhomologous competition. The EC₅₀ and E_(max) values to agonists for[³⁵S]GTPγS binding and β-arrestin-2 translocation were determined byfitting data from individual experiments to sigmoidalconcentration-response curves with variable slope in GraphPad Prism5.04. Final mean and S.E.M. were calculated using individual values fromeach experiment. Functional inhibitory potency (K_(e)) values foragonist dose-response displacement experiments were calculated using theGaddum/Schild EC₅₀ shift calculation or with the following equation:K_(e)=[nanomolar antagonist]/(dose ratio −1), where dose ratio is theratio of the EC₅₀ for an agonist in the presence and absence of anotherligand/inhibitor at a given concentration. K_(e) values fordose-inhibition experiments were calculated with a modified CFeq:K_(e)=IC₅₀/(1+[S]/EC₅₀) where [S] is the concentration of agonist usedand EC₅₀ is the functional potency of the agonist.

Coupling efficiency (e-coupling) values indicated the relationshipbetween the apparent binding affinity K_(i) versus the apparentfunctional potency EC₅₀ of a given agonist ligand and used the equationpKi-pEC₅₀. For the functional inhibitory components of antagonists andpartial agonists, e-coupling represents the relationship between theK_(i) versus the K_(e) of a given ligand (against Dynorphin A for OPRKassays, and against U69,593 for OPRM assays) and used the equationpK_(i)−pK_(e). Efficacy efficiency (e-signal) values indicated the ratioof the E_(max) to a given agonist ligand versus the E_(max) to DynorphinA (or U69,593) and uses the equation E_(max)(controlagonist)/E_(max)(test compound). For inhibitory ligands, e-signal wascalculated using maximal level of inhibition (Imax) normalized from 0(basal, buffer) to 1 (agonist without inhibitor). Bias-coupling(quantification of pathway bias) was evaluated by subtracting the EC₅₀or the K_(e) issued from the G-protein pathway assays by those issuedfrom β-arrestin pathway assays for a given ligand and in a linear (nM)scale. Bias-efficacy in favor of the G-protein pathway was evaluated bydividing the functional activation and the functional inhibition maximumresponses (e-signal) from the G-protein pathway by the beta-arrestinpathway assays for a given ligand.

μ-Opioid Receptor Ibogaine Binding Model

The mouse μ-opioid receptor OPRM co-crystal structure available in theProtein Data Bank (PDB), PDB accession 4dk1, Uniprot accession P42866was used in a model of receptor binding. The mouse OPRM has 94% (global)sequence identity to the corresponding human receptor (Uniprot accessionP35372) and all residues in the binding site are identical. The receptorwas crystallized as a fusion protein (OPRMT-4L) with an irreversiblemorphine antagonist ligand (bound to Lys233, pdb numbering). Allsimulations were performed using the Schrodinger 2014.2 and Desmond2014.2 software suite. For initial docking studies the PDB file wasimported into Maestro 9.5 (Schrodinger) and the standard proteinpreparation workflow was run to assign bond orders and clean up thestructure including hydrogen bond optimization and constrainedminimization. In the preparation process missing side chains were addedusing Prime. The fusion protein was manually cut and removed betweenresidues Val262 and Glu270 to leave just the GPCR transmembrane domain;the cut residues were capped as primary amide (C-terminal) and acetate(N-terminal). A (non-covalent) ligand entry (separate from the chain)was manually created in Maestro. The resulting protein complex was againprocessed via the protein preparation workflow. A docking grid wascreated around the co-crystal ligand using Glide (standard settings).Several small molecules including the morphinan co-crystal ligand(unbound), Ibogaine, Noribogaine and Voacangine were imported as 2D SDFinto Maestro and 3D structure representations were generated usingLigPrep (default settings); two representations (inverted at thetertiary bridgehead nitrogen) were generated for each ligand. These weredocking using Glide SP (standard settings except keeping 5 poses percompound out of 30 for post-minimization). The docked morphinan ligandreproduced the co-crystal almost perfectly. This docked complex was thenoptimized using Prime Refine Protein-Ligand complex (default settings).This complex was then used to generate another docking grid using Glide(default settings around the ligand) followed by Glide SP docking of theprepared ligands. In these results, the top poses of noribogaine andibogaine aligned well the morphinan antagonist (hydrophobic Ibogaine andNoribogaine bicyclic system and ethyl substituent with morphinancyclopropyl residues and the positively charged tertiary amines, whichall form a hydrogen bond to the site chain of Asp147). The μ-ORnoribogaine docking complex was then used in a 12 ns molecular dynamics(MD) simulation. The MD system generation and simulations were performedin Desmond using an all atom system with a membrane model and explicitwater model (ASP). The Desmond software automatically sets up thesystems (adjust charges, adds water molecules) and performs severalrounds of minimization and short simulations before the 12 ns productionrun. MD was run on the Pegasus 2 cluster at the Center for ComputationalScience at the University of Miami (http://ccs.miami.edu/hpc/) using 48processors and completed in less than 19 hours. Simulation analysis wasperformed using the Desmond trajectory analysis software. Arepresentative frame with these most prevalent interactions throughoutthe simulation was extracted from the trajectory, processed via proteinpreparation (including constrained minimization) to remove overlappingatoms, and visualized using PyMol.

5.2: Apparent Binding Affinities of Noribogaine to OPRM and OPRK

Competitive inhibition of [³H]-U69,593 to human OPRK and of [³H]-DAMGOto human OPRM by noribogaine was conducted and compared to ibogaine,18-methoxycoronaridine (18-MC) and various control ligands (FIG. 12,Table 7). Noribogaine exhibited the highest apparent affinity for OPRKwith a K_(i) value of 720±128 nM. Ibogaine displayed a K_(i) of3.68±0.22 μM, while 18-MC had a K_(i) a 1.84±0.12 μM. At the OPRM,noribogaine displayed a K_(i) of 1.52±0.3 μM, while ibogaine and 18-MCK_(i) values were 6.92±0.83 μM and 2.26±0.35 μM respectively. Values ofboth noribogaine and ibogaine for the human OPRM/K receptors werecomparable that of the calf OPRM and OPRK receptors (1.52 and 0.96 μM,Table 7) where noribogaine was previously shown to be ˜30× less affineat OPRD than at OPRK (Pearl, Herrick-Davis et al. 1995). In theseassays, 18-MC was equi-affine to both human OPRK and OPRM, contrary tothe reported 5× selectivity at OPRM (Glick, Maisonneuve et al. 2000).Experimental values, historical values from the literature, and controlligands, are displayed in Table 7 for agonists, partial agonists, andantagonists used in this study.

TABLE 7 Binding affinity of Noribogaine and other drugs at the human mu(OPRM) and kappa (OPRK) opioid receptors. Ki values of Noribogaine,Ibogaine, 18-MC (n ≥ 3). Values for control ligands Morphine, NaloxoneDAMGO, U69,593, Dynorphin A, [Met]-Enkephalin, Nalmefene, Buprenorphinewere determined and/or gathered from the literature. Specificity for theOPRK receptor was evaluated using ΔKi = pKi(OPRK)-pKi(OPRM). Agonists(bold), partial agonists (underline), and antagonists (italics). OPRMOPRK [³H]-DAMGO binding [³H]-U69,593 Binding Specificity Compound pK_(i)K_(i) (nM) SEM pK_(i) K_(i) (nM) SEM ΔpK_(i) References U69,593 N.Q. 9.20.59/0.87 >3 Perkin Elmer/This work DAMGO 9.1 0.6 /0.5 0.2 N.Q. <−3(Toll, Berzetei-Gurske et al. 1998)/ This work Dynorphin A 8.1 7.7 2.28.8 1.7- 0.85- 0.7 (Toll, Berzetei-Gurske et al. 1998)- 0.05** 0.01**(Li, Zhu et al. 1993) [Met]-Enkephalin 9.2 0.63 6.0 1000 <−3 (Meng, Xieet al. 1993) Morphine 9.0 1.1 0.05 7.3 46.9 4.5 −1.6 (Toll,Berzetei-Gurske et al. 1998) Nalmefene 9.0 1 10 0.083 0.0008 1.1 (Bart,Schluger et al. 2005) Buprenorphine 10 0.08 0.02 10 0.11 0.05 −0.1(Huang, Kehner et al. 2001) 6′GNTI 7.1 82 21 8.9 1.15 0.39 1.84 (Sharma,Jones et al. 2001) Noribogaine 5.6 2660* (OPRD- 6.0 960* 0.4 (Pearl,Herrick-Davis et al. 1995) 24720) 5.8 1520 300 6.1 720 128 0.3 This workIbogaine 5.0 11040* (OPRD- 5.4 3770 0.5 (Pearl, Herrick-Davis et al.1995) N.Q.) 5.2 6920 830 5.4 3680 220 0.3 This work 18-MC 6.0 1100* 3005.3 5100* 500 −0.7 (Glick, Maisonneuve et al. 2000) 5.6 2360 350 5.71840 120 0.1 This work Naloxone 8.9 1.4/1.3 0.05 8.6 2.5 0.3 −0.3 (Toll,Berzetei-Gurske et al. 1998)/ This work NorBNI 7.7 21 5 9.7 0.2-0.040.05- 2.0 (Toll, Berzetei-Gurske et al. 1998)- 0.01** (Li, Zhu et al.1993) *: calf receptor; **: [3H]diprenorphine binding; OPRD: humanopioid receptor delta; N.Q. non-quantifiable

5.3: Functional Agonist Properties of Noribogaine at OPRM and OPRK[³⁵S]GTPγS Binding Stimulation

[³⁵S]GTPγS binding to membranes of CHO cells stably transfected withOPRK or OPRM was examined in response to noribogaine, ibogaine,morphine, and nalmefene drug treatment and measured the activation ofthe G-protein pathway by agonists (FIGS. 13A and 13B). The prototypicalfull agonist U69,593, and the endogenous ultra-potent agonist, DynorphinA, were used as controls for OPRK function and DAMGO was used for OPRM.Calculated EC₅₀ and E_(max) values are enumerated in Table 8.

Noribogaine was marginally active at stimulating [³⁵S]GTPγS binding toOPRM, with an E_(max) of 10% the full agonist DAMGO (FIG. 13A) andcomparable to the level of activation previously reported (Antonio,Childers et al. 2013). Morphine was a partial agonist with an E_(max) of80±4.5% of DAMGO signal and an EC₅₀ of 32±1.2 nM. The partial agonistbuprenorphine stimulated OPRM with an E_(max) of 26±2.2% in theseassays, as previously reported (Saidak, Blake-Palmer et al. 2006), andibogaine and 18-MC failed to stimulate the OPRM G-protein pathway.

Noribogaine was a partial agonist at stimulating [³⁵S]GTPγS binding toOPRK with an E_(max) of 72±3.8% of U69,593, and an EC₅₀ of 8.75±1.09 μM(FIG. 13B). Ibogaine displayed a lower agonist power than noribogaine atOPRK with an E_(max) of 18±1.4%, while 18-MC failed to stimulate[³⁵S]GTPγS binding to OPRK. In these assays, morphine and dynorphin Adisplayed E_(max) values of 91±7% and 94±7% respectively, and nalmefene,a partial agonist of OPRK, maximally stimulated at 35±4.7% and similarto formally reported values (Bart, Schluger et al. 2005).

The apparent coupling efficiencies of agonists DAMGO, U69,593, morphine,dynorphin A, nalmefene, 6′GNTI, noribogaine and ibogaine at theG-protein pathway were calculated (see methods) and found to becongruent with values shifted by ˜1 log (Tables 2 and 5). Dynorphin Aand 6′GNTI were outliers and displayed better coupling efficiencies(0.56 and 0.26) than other agonists at stimulating [³⁵S]GTPγS binding incomparison to their apparent binding affinities against [³H]U69,593 and[³H]diprenorphin (Tables 2 and 5).

TABLE 8 Activation and inhibition by Noribogaine of [³⁵S]GTPγS bindingin CHO-K1 stably expressing human OPRM and OPRK. OPRM: [35S]GTPgSBinding Activation Compound EC₅₀ Efficacy Activation/Inhibition pEC₅₀(nM) (SEM) n (%) (SEM) n e-coupling References DAMGO 7.5 29 9 7 100 n.a.1.77 [Met]-Enkephalin 7.4 ~40 ~95 1.8  (Saidak, Blake- Palmer et al.2006) Morphine 7.5 32 1.2 3 80 4.5 4 1.47 Buprenorphine n.d. 26 2.2 2n/d Noribogaine 4.8 16050 9409 4 9.4 1.8 4 1.02 Ibogaine n.d. 2 −2.918-MC n.d. 2 <5 6′GNTI >1000 0~ (Waldhoer, Fong et al. 2005) Noribogaine(Ke) 4.7 19203 5168 −100~ 1.10 Naloxone (Ke) 8.5 3.36 0.75 −100 0.38PRK: [35S]GTPgS Binding Activation Compound EC₅₀ EfficacyActivation/Inhibition pEC₅₀ (nM) (SEM) n (%) (SEM) n e-couplingReferences U69,593  8.1 7.25 0.9  9  100 n.a. 0.92  Dynorphin A  9.70.18 0.04  6   94 7  3 0.56  Morphine  6.4 434 67  4   91 7  3 0.97 Noribogaine  5.1 8749 1092 10   72 3.8 14 1.08  Nalmefene  9.2 0.69 0.14 3   35 4.7  3 0.92  6′GNTI  8.7 2.1 0.5   37 2 0.26  (Schmid, Streicheret al. 2013) Ibogaine  4.9 12000~  2   18 1.4 1.39~ 18-MC  4.8 16000~  2  <5 0.94~ Noribogaine (Ke)-U69  4.9 11560 786  −30 1.22 Noribogaine(Ke)-Dyn  4.4 39797 15560  −25 1.72 Nalmefene (Ke)  9.9 0.14 0.04  −650.23 6′GNTI (Ke)  9.7 0.18  −32 −0.81   Adapted from (Schmid, Streicheret al. 2013) 18-MC (Ke)  5.3 4556 1392 −100 0.39  NorBNI (Ke) 10.50.03269 −100 −0.1    Naloxone (Ke)  8.5 3.36 0.75 −100 0.13  n/anon-applicable. n/d not determined Data used for the non-linearregression analysis are shown as the mean ±SEM of (n) experiments.[Met]-Enkephalin and 6′GTNI values were gathered from references asindicated. Non-italic section indicates values (EC50) for the activationcomponent of the ligand and italic section indicates the values (Ke) forthe inhibitory component of the ligand. Coupling efficiency (e-coupling)was calculated as in methods. Outliers are underlined.

5.4: Functional Inhibitory Properties of Noribogaine at OPRM [³⁵S]GTPγSBinding Stimulation

Noribogaine marginally stimulated [³⁵S]GTPγS binding via OPRM with anapproximated EC₅₀ of 16 μM (FIG. 13A). Therefore, whether noribogaine isan antagonist of OPRM was investigated. DAMGO and morphine doseresponses were carried out in the presence and absence of 150 μM ofnoribogaine (FIG. 14A). Noribogaine was an inhibitor of both agoniststested and right-shifted their EC₅₀ by a magnitude of ˜1 log. Thecalculated K_(e) values (see methods) were 19±5 μM against DAMGO and28±14 μM against morphine (Table 8) and both were in the concentrationrange of the EC₅₀ of noribogaine at OPRM G-protein pathway. In a similardesign, naloxone displayed a K_(e) of 3.36±0.75 nM, a value close to itsKat OPRM (Tables 7 and 8). Noribogaine also decreased the E_(max) ofboth DAMGO and morphine dose-responses curves in this assay (FIG. 14A),indicating partial unsurmountable antagonism that can encompass severaldistinct molecular mechanisms such as (a) irreversible competitiveantagonism, (b) noncompetitive antagonism, and/or (c) functionalantagonism; for review (Neubig, Spedding et al. 2003). Dose-inhibitioncurves of noribogaine against increasing doses of DAMGO were performed(FIG. 14B). Noribogaine dose-dependently inhibited DAMGO-stimulated[³⁵S]GTPγS binding at OPRM with an IC₅₀ of 134±17 μM, independent of theagonist concentrations of DAMGO.

5.5: Functional Inhibition of Noribogaine-Induced OPRK [³⁵S]GTPγSBinding by Antagonists

Inhibitory effects of naloxone, Nor-BNI, and nalmefene on theagonist-induced [³⁵S]GTPγSyS binding to OPRK by noribogaine and U69,593,Dynorphin A, morphine, and nalmefene were investigated (FIG. 15, Table9). Dose-responses to these agonists were gathered in the absence andpresence of fixed antagonist concentration: 30 nM Naloxone, 5 nMNor-BNI, and 3 nM nalmefene. The compound 18-MC was also tested, whichappeared to be an antagonist in this assay with a K_(e) of 4.5±1.4 μMagainst U69,593.

Antagonists and partial agonist nalmefene dose-dependently right-shiftedthe dose-response curves of noribogaine, consistent with the addition ofa surmountable competitor of the noribogaine binding site (FIG. 15).Functional inhibition constants (K_(e)) for antagonists are shown inTable 9 with the assumption of ideal conditions of competitiveness andequilibrium. In all instances, the functional inhibition constants forthese inhibitors were close to their indicating that noribogaine was nodifferent than other agonists tested and was apparently competing for acommon binding site.

TABLE 9 Functional inhibition constants Ice of Noribogaine and otherligands to agonist-induced [³⁵S]GTPγS binding in CHO-K1 stablyexpressing human OPRK. Antagonists & Rival Agonists agonists Ke (nM)U69′593 Dynorphin A Morphine Noribogaine Nalmefene K_(i) EC₅₀ U69′593n/a n/a n/d 0.4 4 0.9 7.3 Dynorphin A n/a n/a n/a 0.003 0.1 0.05 0.18Morphine n/d n/a n/a 74 270 47 434 Noribogaine 12e3 ± 0.8e3 40e3 = 16e315e3 ± 4e3 n/a 24e3 700 8.7e3 Nalmefene 0.14 ± 0.04 0.077 ± 0.016  0.11± 0.005 0.33 ± 0.07 n/a 0.08 0.7 Naloxone 8.6 ± 1.3 4.8 ± 0.9 8.2 ± 1.24.2 ± 2.3 9.2 2.5 n/a NorBNI 0.12 ± 0.04 0.029 ± 0.004  0.07 ± 0.0130.075 ± 0.036 0.1 ± 0.09 0.2 n/a 18-MC 4.5e3 ± 1.4e3 2.8e3 ± 0.6e3 2.9e3± 0.7e3 4.3e3 ± 1.9e3 n/d 1.8e3 n/a n/a non-applicable. n/d notdetermined Data used for the non-linear regression analysis are shown asthe mean ± SEM of 3 up to 7 experiments. Italic value represents theestimate of a hypothetical functional activation constant of designatedagonist in the presence of other agonists.

5.6: Residual Functional Antagonist Properties of Noribogaine at OPRK[³⁵S]GTPγS Binding Stimulation

Noribogaine was a partial agonist at OPRK in the [³⁵S]GTPγS bindingstimulation assays (FIG. 13). Therefore, it was investigated whethernoribogaine, termed here as ‘rival agonist’, and the partial agonistnalmefene was able to functionally compete with and level down theactivity of more efficacious agonists than itself.

Dynorphin A and morphine dose-responses curves were performed in thepresence and the absence of rival agonists nalmefene or noribogaine atconcentrations of ˜5× their EC₅₀ (nalmefene 3 nM, noribogaine 50 μM)(FIGS. 16A and 16C). Nalmefene readily right-shifted the EC₅₀ ofDynorphin A and morphine with an apparent K_(e) of 0.077±0.016 nM and0.11±0.005 nM, within the range of its apparent Ki (0.08 nM) and similarto the pure antagonist NorBNI (Table 9). Noribogaine, on the other hand,poorly right-shifted the EC₅₀ of these agonists and the K_(e) estimatesin these conditions were 40±16 μM and 15±4 μM respectively, about 40×its K. (Table 9, underlined values).

In another set of experiments (FIGS. 16B and 16D), noribogaine andnalmefene dose-response curves were produced in the presence of a setconcentration of agonists. Nalmefene readily leveled-down the signal ofmoderate to high concentrations of rival full (U69,593) or partial(noribogaine) agonists to its own reduced levels (30%) with an apparentIC₅₀ proportional to the rival agonist concentration (includingnoribogaine). Noribogaine also leveled-down the signal of highconcentrations of rival agonists to its own reduced signal (70%), butthe IC₅₀ values were high (100-300 μM range). Finally, the apparentfunctional potency of dynorphin A, U69'593 and morphine were estimatedby being set as rival agonist dose-responses in the presence of eithernoribogaine or nalmefene. In this setting, the calculated K_(e)(activation) for all rival agonists were lower in the presence ofnoribogaine than in the presence of nalmefene (close to theirexperimental EC₅₀) and showed that noribogaine was a somewhat poorfunctional blocker of these agonists (Table 9, underlined values).

5.7: Functional Antagonist Properties of Noribogaine at OPRK-Mediatedβ-Arrestin-2 Recruitment

PathHunter β-Arrestin GPCR assays detecting the interaction ofβ-Arrestin with the activated receptor were used to measure non-Gprotein OPRM&K activity as in (Violin, Crombie et al.). Dose-responsecurves to noribogaine were compared to full agonists [Met]-enkephalin(OPRM), and Dynorphin A (OPRK) drug treatments (FIGS. 17A and 17B).Calculated EC₅₀ values, maximal responses and coupling efficiencies areshown in Table 10. Control agonist [Met]-Enkephalin displayed an EC₅₀ of193±11 nM at OPRM and Dynorphin A displayed an EC₅₀ of 82±21 nM at OPRK.Noribogaine displayed a profound functional bias at OPRK and wasmarginally efficacious at inducing β-Arrestin-2 recruitment at OPRK withan E_(max) of 12.6±3% of dynorphin A maximal stimulation and anestimated EC₅₀ of 265 nM. Noribogaine was also not an agonist at OPRM.

Noribogaine was then tested for its ability to inhibit agonist-inducedβ-Arrestin-2 recruitment at OPRM and OPRK (FIGS. 17A and 17B). In theseassays, β-Arrestin-2 recruitment was induced by the agonists[Met]-Enkephalin (OPRM) and Dynorphin A (OPRK) at their EC₅₀concentration and challenged with increasing concentrations ofnoribogaine. Noribogaine inhibited agonist responses at OPRM and OPRK upto 60-100% and ˜60%, with an IC₅₀ of ˜57 μM and 1.45±1.1 04 respectively(FIG. 18). The K_(e) values were ˜4.8 μM and 262 nM for OPRM and OPRKrespectively (Table 10). Thus, noribogaine was apparently 144× morepotent at inhibiting Dynorphin A-induced β-arrestin-2 recruitment thanat inhibiting Dynorphin A-induced G-protein activation (Table 11).

TABLE 10 Activation and inhibition by Noribogaine of β-arrestin 2recruitment in CHO-K1 stably expressing human OPRM and OPRK. OPRM:β-arrestin 2 recruitment Compound EC₅₀ Efficacy Activation/InhibitionpEC₅₀ (nM) (SEM) (%) (SEM) e-coupling References DAMGO 6.1   794 100 3.20 (DeWire, Yamashita et al. 2013) [Met]-Enkephalin 6.7   193 11 100 1.94 Morphine 6.3   501 11.3  2.66 (DeWire, Yamashita et al. 2013)Buprenorphine n/a 0 n/a (DeWire, Yamashita et al. 2013) Noribogaine 5.9~1150 3 0.5 n/a Noribogaine (Ke) 4.2 ~4794 −100~ ~1.10 OPRK: β-arrestin2 recruitment Compound EC₅₀ Efficacy Activation/Inhibition pEC₅₀ (nM)(SEM) (%) (SEM) e-coupling References U69′593 7.2 59 100  1.83 (Schmid,Streicher et al. 2013) Dynorphin A 7.1 82 21 100  3.22 Noribogaine 6.6~265 12.6 3 −0.43 6′GNTI 8.2 5.9 3.3 12 3  0.71 (Schmid, Streicher etal. 2013) Noribogaine (Ke)-Dyn 6.6 262 −60~ −0.44 6′GNTI (Ke) 9.3 0.56−69 2 −0.31 Adapted from (Schmid, Streicher et al. 2013) NorBNI (Ke) 9.40.37 −100  0.27 Data used for the non-linear regression analysis areshown as the mean ± SEM of one standardized experiment. Morphine,buprenorphine and 6′GTNI values were gathered from references asindicated. Non-italic section indicates values (EC50) for the activationcomponent of the ligand and italic section indicates the values (Ke) forthe inhibitory component of the ligand. Coupling efficiency (e-coupling)was calculated as in methods.

TABLE 11 Noribogaine activation and inhibition bias quantification atOPRK. G-protein Pathway Beta-Arrestin2 Pathway BiasG-protein/Beta-arrestin2 Activation e-coupling e-signal e-couplinge-signal Bias-coupling Bias-efficacy U69′593  0.92 1.00  1.83 1.00 1/8 0Dynorphin A  0.56 0.94  3.22 1.00   1/457 −0.06 Noribogaine  1.08 0.72−0.43 0.13  32 0.59 6′GTNI  0.26 0.37  0.71 0.12 1/3 0.25 Inhibitione-coupling e-signal e-coupling e-signal Bias-coupling Bias-efficacyNoribogaine  1.72 0.25 −0.44 0.60 144 −0.35 6′GTNI −0.81 0.32 −0.31 0.691/3 −0.37

5.8: Binding Model of Noribogaine and Ibogaine to the InactiveConformation of OPRM

An in silico binding model was developed based on the mouse OPRMco-crystal structure [PMID 22437502] (Manglik, Kruse et al. 2012) asdescribed in methods. The mouse and human OPRM share 94% (global)sequence identity and all binding site residues are identical. Afterinitial optimization of the model, the top docking poses of noribogaineand ibogaine were pharmacophorically aligned with the co-crystalmorphinan antagonist as one would expect: the hydrophobic ibogaine andnoribogaine bicyclic system and ethyl substituent with morphinancyclopropyl residues were spatially aligned and the positively chargedtertiary amines were superimposed with each forming a hydrogen bond tothe site chain of Asp147. Then, the noribogaine and ibogaine OPRMcomplexes were each used in a 12 ns all atom explicit water moleculardynamics simulation (see methods). Trajectory analysis revealed the mostprevalent interactions of noribogaine (FIG. 18) and ibogaine. Bothligands formed a stable hydrogen bond with Asp147 via their tertiaryamine. Noribogaine and ibogaine formed pi-cation interaction with Tyr148(64 and 56%, respectively), and hydrophobic interactions with His297 (64and 93%, respectively). Further hydrophobic interactions were observedbetween Val236 (˜40 and ˜60%, respectively), Tyr326 (˜20 and ˜40%respectively), Met151 (˜20% and ˜30%, respectively) and also Trp293,Ile296, Val300. Characteristically, noribogaine, but not ibogaine,formed a water bridge with Tyr148 for 34% of the simulation time. Bothligands showed a hydrogen bond with His297 for about 20% of thesimulation. A representative illustration frame of noribogaine in theOPRM was extracted from the simulation and is shown in FIG. 19.

Discussion

Historically, in vivo studies excluded the possibility of prototypicalagonistic mechanism of ibogaine and noribogaine at the mu and/or kappaopioid receptors while potential antagonistic mechanisms were also notconclusive. These ambiguous results lead research groups to providenon-opioid mechanistic explanations to the effects of ibogaine andnoribogaine with opiate drugs and in the opioid system. This study nowdemonstrates that noribogaine is in fact a mixed agonist-antagonist ofOPRK and OPRM as well as a profound G-protein biased OPRK ligand.Ibogaine and 18-MC were either not agonists or poor agonists of OPRM orOPRK. 18-MC was a regular competitive antagonist of agonist-induced OPRKsignaling. Thus, noribogaine belongs to a different class of opioidligands than ibogaine or 18-MC.

Pharmacological manipulations, especially with partial agonists, of theOPRK/dynorphin tone may hold potential for the treatment of certain drugaddictions and psychiatric comorbidity. Finally, it was shown thatnoribogaine triggered the release of prolactin in rats and that thiseffects was centrally mediated (Baumann, Rothman et al. 2001). Eithoutbeing boud by theory, it is believed that noribogaine-induced prolactinrelease is mediated by the direct activation of OPRK, similar to whatwas proposed for nalmefene (Bart, Schluger et al. 2005)

In line with their localization in the hippocampus, amygdala,hypothalamus, striatum and spinal cord, the function of the OPRK arerelated to learning and memory, emotional control, stress response andpain (Schwarzer 2009; Bruchas, Land et al. 2010; Butelman, Yuferov etal. 2012). OPRK agonists hold therapeutic potential for mood andaddiction disorders, psychiatric co-morbidities, and pain management,but they also induce undesirable on-target side effects such as placeaversion, dysphoria and anhedonia. On the other hand, OPRK antagonistshold therapeutic potential as antidepressants and anxiolytics, but mayinduce hyperalgic states. Recent elegant studies in rodents havemechanistically linked the activation of p38 MAPK to stress-mediatedOPRK stimulation via the β-arrestin mediated transduction pathway(Bruchas, Macey et al. 2006; Bruchas, Land et al. 2007). In this frame,OPRK G-protein biased agonists were described as hypothetical analgesicdrugs without aversive and dysphoric components (Chavkin 2011). In tstudy, noribogaine was found to be a partial agonist (70%) at the OPRKG-protein pathway. It also displayed profound functional bias and wasnot an agonist of the OPRK β-arrestin pathway. Therefore, noribogaineappears to carry the prerequisite pharmacological characteristics ofanalgesic kappa opioid drug devoid of aversive and dysphoric effects.

Only one ligand as so far been reported to be a G protein-biased OPRKagonist that poorly recruits β-arrestin (Rives, Rossillo et al. 2012).6′-guanidinonaltrindole (6′-GNTI) acts as a β-arrestin antagonist in thepresence of unbiased OPRK agonists, just as noribogaine does in thepresent study. However, noribogaine differs from 6′-GNTI in severalaspects. Noribogaine was more biased than 6′-GNTI with a 2.4× strongerefficacy bias than 6′GNTI (70%−12%=0.59 versus 37%−12%=0.25) (Tables 4,5). Noribogaine displayed an apparent functional coupling bias of 32×for activation (EC₅₀[G-protein]=8 μM vs EC₅₀[β-Arrestin]=265 nM) and144× for inhibition (K_(e)[G-protein]=48 μM vs K_(e)[β-Arrestin]=262 nM)which was not observed for 6′GNTI. At a set concentration correspondingto physiological levels in the brain of rats (e.g. 5 μM) noribogainetested in vitro preserved signaling of Dynorphin A to the G-proteinpathway while markedly inhibiting dynorphin A-induced β-arrestinrecruitment and thereby incurring functional selectivity to theotherwise unbiased endogenous agonist dynorphin A. This peculiarpharmacological property could contribute to anti-dysphoric activitiesagainst stress-induced, drug-activated or over-activedynorphin-kappergic system as seen during drug dependence, withdrawals,stress and anxiety related disorders.

Ligand-induced functional selectivity of otherwise unbiased agonists waspreviously demonstrated for some receptors of the GPCR family (i.e. theallosteric ligand LPI805 for the NK2 receptor (Maillet, Pellegrini etal. 2007). However, in the present study noribogaine does not appear tobe an allosteric ligand and has many features of an OPRK orthostericligand: 1) it directly competed with the binding of orthostericradiolabelled agonists DAMGO, U69,593; 2) it displayed functionallycompetitive behavior with certain antagonists and agonists; 3) it wasdocked to the morphiman orthosteric binding site of the OPRM inactivestate in silico with a good stringency. The data provided herein suggestthat noribogaine induces functional selectivity to dynorphin A via theinterplay of a set of active and inactive conformational states. Certainconformations would be easily accessible to other agonists (the inactiveconformations and active G-protein conformations) and otherconformations would be energetically challenging to populate in theplace of noribogaine (non-recruiting β-arrestin-2 receptorconformations). Indeed, multiple studies provide evidence for theexistence of intermediate conformational states linking the inactivereceptor to the fully active receptor and agonist binding and activationof GPCRs has been proposed to occur through a multistep process. Theintermediate conformational states generated during multistep agonistbinding may have unique functional properties as it is known that GPCRcan couple to different G-proteins and also activate non-G proteindependent pathways. Interestingly, recent investigations in drug designdescribed an allotropic binding mode for certain OPRK agonists, whichencompassed sequential drug-receptor interaction mechanisms (Munro, Xuet al. 2013).

In conclusion, this study shows that noribogaine is a dual ligand ofboth mu and kappa opioid receptors (OPRM and OPRK) with peculiarpharmacological properties. Noribogaine displayed mixedagonism-antagonism properties and a profound G-protein bias at theopioid receptors. Noribogaine also incurred functional selectivity tothe otherwise unbiased dynorphin A signaling and the kappa system. Thisstudy clarifies the mechanisms of noribogaine at modulating opioidreceptor function, proposing explanatory mechanisms for the knownmodulatory properties of noribogaine at the opioid system in vivo aswell as new avenues of therapeutic development and applicability.

All references cited are incorporated by reference herein in theirentireties.

What is claimed is:
 1. A pharmaceutical formulation comprising (a) atleast one opioid analgesic, (b) an effective amount of iboga alkaloid orpharmaceutically acceptable salt and/or solvate thereof to potentiatethe effect of the opioid as an analgesic, and (c) optionally apharmaceutically acceptable carrier.
 2. The pharmaceutical formulationof claim 1, wherein the effective amount of iboga alkaloid orpharmaceutically acceptable salt and/or solvate thereof is between about5 mg and about 50 mg.
 3. The pharmaceutical formulation of claim 1,wherein the ratio of iboga alkaloid or pharmaceutically acceptable saltand/or solvate thereof to opioid analgesic in the formulation is betweenabout 1:100 and about 100:1.
 4. The pharmaceutical formulation of claim1, wherein the ratio of iboga alkaloid or pharmaceutically acceptablesalt and/or solvate thereof to opioid analgesic in the formulation isbetween about 1:100 and about 1:1.
 5. The pharmaceutical formulation ofclaim 1, wherein the opioid analgesic is selected from the groupconsisting of fentanyl, hydrocodone, hydromorphone, morphine, oxycodone,buprenorphine, codeine, thebaine, buprenorphine, methadone, meperidine,tramadol, tapentadol, levorphanol, sufentanil, pentazocine, andoxymorphone.
 6. The pharmaceutical formulation of claim 5, wherein theopioid analgesic is selected from the group consisting of buprenorphine,hydromorphone, hydrocodone, morphine, and oxycodone.
 7. Thepharmaceutical formulation of claim 1, comprising between about 5 mg andabout 250 mg opioid analgesic.
 8. The pharmaceutical formulation ofclaim 1, wherein the iboga alkaloid is noribogaine, noribogainederivative, or pharmaceutically acceptable salt and/or solvate thereof.9. The pharmaceutical formulation of claim 8, wherein the noribogainederivative is represented by Formula I:

or a pharmaceutically acceptable salt thereof, wherein R is hydrogen ora hydrolyzable group of the formula:

wherein X is an unsubstituted C₁-C₁₂ group or a C₁-C₁₂ group substitutedby lower alkyl or lower alkoxy groups, wherein the noribogaine havingthe hydrolyzable group hydrolyzes in vivo to form 12-hydroxy ibogamine.10. The pharmaceutical formulation of claim 8, wherein the noribogainederivative is represented by Formula II:

or a pharmaceutically acceptable salt thereof, wherein

is a single or double bond; R¹ is halo, OR², or C₁-C₁₂ alkyl optionallysubstituted with 1 to 5 R¹⁰; R² is hydrogen or a hydrolysable groupselected from the group consisting of —C(O) R^(x), —C(O)OR^(x) and—C(O)N(R^(y))₂ where each R^(x) is selected from the group consisting ofC₁-C₆ alkyl optionally substituted with 1 to 5 R¹⁰, and each R^(y) isindependently selected from the group consisting of hydrogen, C₁-C₆alkyl optionally substituted with 1 to 5 R¹⁰, C₆-C₁₄ aryl optionallysubstituted with 1 to 5 R¹⁰, C₃-C₁₀ cycloalkyl optionally substitutedwith 1 to 5 R¹⁰, C₁-C₁₀ heteroaryl having 1 to 4 heteroatoms and whichis optionally substituted with 1 to 5 R¹⁰, C₁-C₁₀ heterocyclic having 1to 4 heteroatoms and which is optionally substituted with 1 to 5 R¹⁰,and where each R^(y), together with the nitrogen atom bound thereto forma C₁-C₆ heterocyclic having 1 to 4 heteroatoms and which is optionallysubstituted with 1 to 5 R¹⁰ or a C₁-C₆ heteroaryl having 1 to 4heteroatoms and which is optionally substituted with 1 to 5 R¹⁰; R³ isselected from the group consisting of hydrogen, C₁-C₁₂ alkyl optionallysubstituted with 1 to 5 R¹⁰, aryl optionally substituted with 1 to 5R¹⁰, —C(O)R⁶, —C(O)NR⁶R⁶ and —C(O)OR⁶; R⁴ is selected from the groupconsisting of hydrogen, —(CH₂)_(m)OR⁸, —CR⁷(OH)R⁸, —(CH₂)_(m)CN,—(CH₂)_(m)COR⁸, —(CH₂)_(m)CO₂R⁸, —(CH₂)_(m)C(O)NR⁷R⁸,—(CH₂)_(m)C(O)NR⁷NR⁸R⁸, —(CH₂)_(m)C(O)NR⁷NR⁸C(O)R⁹, and —(CH₂)_(m)NR⁷R⁸;m is 0, 1, or 2; L is a bond or C₁-C₁₂ alkylene; R⁵ is selected from thegroup consisting of hydrogen, C₁-C₁₂ alkyl substituted with 1 to 5 R¹⁰,C₁-C₁₂ alkenyl substituted with 1 to 5 R¹⁰, —X¹—R⁷, —(X¹—Y)_(n)—X¹—R⁷,—SO₂NR⁷R⁸, —O—C(O)R⁹, —C(O)OR⁸, —C(O)NR⁷R⁸, —NR⁷R⁸, —NHC(O)R⁹, and—NR⁷C(O)R⁹; each R⁶ is independently selected from the group consistingof hydrogen, C₁-C₁₂ alkyl, C₂-C₁₂ alkenyl, C₂-C₁₂ alkynyl, C₆-C₁₀ aryl,C₁-C₆ heteroaryl having 1 to 4 heteroatoms, and C₁-C₆ heterocycle having1 to 4 heteroatoms, and wherein the alkyl, alkenyl, alkynyl, aryl,heteroaryl, and heterocycle are optionally substituted with 1 to 5 R′°;X¹ is selected from the group consisting of 0 and S; Y is C₁-C₄ alkyleneor C₆-C₁₀ arylene, or a combination thereof; n is 1, 2, or 3; R⁷ and R⁸are each independently selected from the group consisting of hydrogen,C₁-C₁₂ alkyl optionally substituted with 1 to 5 R¹⁰, C₁-C₆ heterocyclehaving 1 to 4 heteroatoms and which is optionally substituted with 1 to5R¹⁰, C₃-C₁₀ cycloalkyl optionally substituted with 1 to 5 R¹⁰, C₆-C₁₀aryl optionally substituted with 1 to 5 R¹⁰ and C₁-C₆ heteroaryl having1 to 4 heteroatoms optionally substituted with 1 to 5 R¹⁰; R⁹ isselected from the group consisting of C₁-C₁₂ alkyl optionallysubstituted with 1 to 5 R¹⁰, C₁-C₆ heterocycle having 1 to 4 heteroatomsoptionally substituted with 1 to 5 R¹⁰, C₃-C₁₀ cycloalkyl optionallysubstituted with 1 to 5 R¹⁰, C₆-C₁₀ aryl optionally substituted with 1to 5 R¹⁰ and C₁-C₆ heteroaryl having 1 to 4 heteroatoms optionallysubstituted with 1 to 5 R¹⁰; R¹⁰ is selected from the group consistingof C₁-C₄ alkyl, phenyl, halo, —OR¹¹, —CN, —COR¹¹, —CO₂R¹¹, —C(O)NHR¹¹,—NR¹¹R¹¹, —C(O)NR¹¹R¹¹, —C(O)NHN HR¹¹, —C(O)NR¹¹NHR¹¹, —C(O)NR¹¹NR¹¹R¹¹,—C(O)NHNR¹¹C(O)R¹¹, —C(O)NHNHC(O)¹¹, —SO₂NR¹¹R¹¹, —C(O)NR¹¹NR¹¹C(O)R¹¹,and —C(O)NR¹¹NHC(O)R¹¹; and R¹¹ is independently hydrogen or C₁-C₁₂alkyl; provided that: when L is a bond, then R⁵ is not hydrogen; when

is a double bond, R¹ is an ester hydrolyzable group, R³ and R⁴ are bothhydrogen, then -L-R⁵ is not ethyl; when

is a double bond, R¹ is —OH, halo or C₁-C₁₂ alkyl optionally substitutedwith 1 to 5 R¹⁰, then R⁴ is hydrogen; and when

is a double bond, R¹ is OR², R⁴ is hydrogen, -L-R⁵ is ethyl, then R² isnot a hydrolyzable group selected from the group consisting of an ester,amide, carbonate and carbamate.
 11. The pharmaceutical formulation ofclaim 8, wherein the noribogaine derivative is represented by FormulaIII:

or a pharmaceutically acceptable salt thereof, wherein

is a single or double bond; R¹² is halo, —OH, —SH, —NH₂, —S(O)₂N(R¹⁷)₂,—R^(z)-L¹-R¹⁸, —R^(z)-L¹-R¹⁹, —R^(z)-L¹-R²⁰ or —R^(z)-L¹-CHR¹⁸R¹⁹, whereR^(z) is O, S or NR¹⁷; L¹ is alkylene, arylene, —C(O)-alkylene,—C(O)-arylene, —C(O)O-arylene, —C(O)O-alkylene, —C(O)NR²⁰-alkylene,—C(O)NR²⁰-arylene, —C(NR²⁰)NR²⁰-alkylene or —C(NR²⁰)NR²⁰-arylene,wherein L¹ is configured such that —O-L¹-R¹⁸ is —OC(O)-alkylene-R¹⁸,—OC(O)O-arylene-R¹⁸, —OC(O)O-alkylene-R¹⁸, —OC(O)-arylene-R²⁰,—OC(O)NR²⁰-alkylene-R¹⁸, —OC(O)NR²⁰-arylene-R¹⁸, —) OC(NR²⁰)NR²⁰-alkylene-R¹⁸ or —OC(NR²⁰)NR²⁰-arylene-R¹⁸, and wherein the alkyleneand arylene are optionally substituted with 1 to 2 R¹⁶; R^(—)ishydrogen, —S(O)₂OR²⁰, —S(O)₂R²⁰, —C(O)R¹⁵, —C(O)NR¹⁵R¹⁵, —C(O)OR¹⁵,C₁-C₁₂ alkyl optionally substituted with 1 to 5 R¹⁶, C₁-C₁₂ alkenyloptionally substituted with 1 to 5 R¹⁶, or aryl optionally substitutedwith 1 to 5 R¹⁶; R¹⁴ is hydrogen, halo, —OR¹⁷, —CN, C₁-C₁₂ alkyl, C₁-C₁₂alkoxy, aryl or aryloxy, where the alkyl, alkoxy, aryl, and aryloxy areoptionally substituted with 1 to 5 R¹⁶; each R¹⁵ is independentlyselected from the group consisting of hydrogen, C₁-C₁₂ alkyl, C₂-C₁₂alkenyl, C₂-C₁₂ alkynyl, aryl, heteroaryl, and heterocycle, and whereinthe alkyl, alkenyl, alkynyl, aryl, heteroaryl, and heterocycle areoptionally substituted with 1 to 5 R¹⁶; R¹⁶ is selected from the groupconsisting of phenyl, halo, —OR¹⁷, —CN, —COR¹⁷, —CO₂R¹⁷, —NR¹⁷R¹⁷,—NR¹⁷C(O)R¹⁷, —NR¹⁷SO₂R¹⁷, —C(O)NR¹ 7R¹⁷, —C(O)NR¹⁷NR¹⁷, —SO₂NR¹⁷R¹⁷ and—C(O)NR¹⁷NR¹⁷C(O)R¹⁷; each R¹⁷ is independently hydrogen or C₁-C₁₂ alkyloptionally substituted with from 1 to 3 halo; R¹⁸ is hydrogen, —C(O)R²⁰,—C(O)OR²⁰, —C(O)N(R²⁰)₂ or —N(R²⁰)C(O)R²⁰, R¹⁹ is hydrogen, —N(R²⁰)₂,—C(O)N(R²⁰)₂, —C(NR²⁰)N(R²⁰)₂, —C(NSO₂R²⁰)N(R²⁰)₂, —NR²⁰C(O) N(R²⁰)₂,—NR²⁰C(S)N(R²⁰)₂, —NR²⁰C(NR²⁰)N(R²⁰)₂, —NR²⁰C(NSO₂R²⁰)N(R²⁰)₂ ortetrazole; and each R²⁰ is independently selected from the groupconsisting of hydrogen, C₁-C₁₂ alkyl and aryl; provided that: when

is a double bond and R^(—)and R¹⁴ are hydrogen, then R¹² is not hydroxy;when

is a double bond, R¹⁴ is hydrogen, R¹² is —O-L¹-R¹⁸, —O-L¹-R¹⁹,—O-L¹-R²⁰, and L¹ is alkylene, then —O-L¹-R¹⁸, —O-L¹-R¹⁹, —O-L¹-R²⁰ arenot methoxy; when

is a double bond, R¹⁴ is hydrogen, R^(z) is O, L¹ is —C(O)-alkylene,—C(O)-arylene, —C(O)O-arylene, —C(O)O-alkylene, —C(O)NR²⁰-alkylene, or—C(O)NR²⁰-arylene, then none of R¹⁸, R¹⁹ or R²⁰ are hydrogen.
 12. Thepharmaceutical formulation of claim 8, wherein the noribogainederivative is represented by Formula IV:

or a pharmaceutically acceptable salt thereof, wherein R²¹ is selectedfrom the group consisting of hydrogen, a hydrolysable group selectedfrom the group consisting of —C(O)R²³, —C(O)NR²⁴R²⁵ and —C(O)OR²⁶, whereR²³ is selected from the group consisting of hydrogen, alkyl,substituted alkyl, alkenyl, substituted alkenyl, alkynyl and substitutedalkynyl, R²⁴ and R²⁵ are independently selected from the groupconsisting of hydrogen, alkyl, substituted alkyl, alkenyl, substitutedalkenyl, alkynyl, substituted alkynyl, aryl, substituted aryl,heteroaryl, substituted heteroaryl, heterocyclic and substitutedheterocyclic, R²⁶ is selected from the group consisting of alkyl,substituted alkyl, alkenyl, substituted alkenyl, alkynyl, substitutedalkynyl, aryl, substituted aryl, heteroaryl, substituted heteroaryl,heterocyclic and substituted heterocyclic, provided that R²¹ is not asaccharide or an oligosaccharide; L² is selected from the groupconsisting of a covalent bond and a cleavable linker group; R²² isselected from the group consisting of hydrogen, alkyl, substitutedalkyl, alkenyl, substituted alkenyl, alkynyl, substituted alkynyl, aryl,substituted aryl, cycloalkyl, substituted cycloalkyl, heteroaryl,substituted heteroaryl, heterocyclic, and substituted heterocyclic,provided that R is not a saccharide or an oligosaccharide; provided thatwhen L² is a covalent bond and R²² is hydrogen, then R²¹ is selectedfrom the group consisting of —C(O)NR²⁴R²⁵ and —C(O)OR²⁶; and furtherprovided that when R²¹ is hydrogen or —C(O)R²³ and L² is a covalentbond, then R²² is not hydrogen.
 13. The pharmaceutical formulation ofclaim 8, wherein the noribogaine derivative is represented by Formula V:

or a pharmaceutically acceptable salt thereof, wherein:

refers to a single or a double bond provided that when

is a single bond, Formula V refers to the corresponding dihydrocompound; R²⁷ is hydrogen or SO₂OR²⁹; R²⁸ is hydrogen or SO₂OR²⁹; R²⁹ ishydrogen or C₁-C₆ alkyl; provided that at least one of R²⁷ and R²⁸ isnot hydrogen.
 14. The pharmaceutical formulation of claim 8, wherein thenoribogaine derivative is represented by Formula VI:

or a pharmaceutically acceptable salt thereof, wherein:

refers to a single or a double bond provided that when

is a single bond, Formula VI refers to the corresponding vicinal dihydrocompound; R³⁰ is hydrogen, a monophosphate, a diphosphate or atriphosphate; and R³¹ is hydrogen, a monophosphate, a diphosphate or atriphosphate; provided that both R³⁰ and R³¹ are not hydrogen; whereinone or more of the monophosphate, diphosphate and triphosphate groups ofR³⁰ and R³¹ are optionally esterified with one or more C₁-C₆ alkylesters.
 15. The pharmaceutical formulation of claim 1, wherein the ibogaalkaloid is noribogaine or a pharmaceutically acceptable salt and/orsolvate thereof.
 16. A method for potentiating the analgesic effect ofan opioid analgesic in a patient undergoing or scheduled to undergoopioid analgesic therapy, the method comprising administering apotentiating amount of an iboga alkaloid or pharmaceutically acceptablesalt and/or solvate thereof while maintaining a QT interval prolongationof less than about 60 milliseconds (ms) during said treatment, therebypotentiating the effect of the opioid.
 17. A method for preventing orreducing tolerance to an opioid analgesic in a patient undergoing orscheduled to undergo opioid analgesic therapy, the method comprisingadministering an effective amount of an iboga alkaloid orpharmaceutically acceptable salt and/or solvate thereof to prevent orreduce tolerance to the opioid while maintaining a QT intervalprolongation of less than about 60 milliseconds (ms) during saidtreatment, thereby preventing or reducing tolerance to the opioid.